A wicked early look at 2020 Senate and gubernatorial races

In recent posts, I began to take a wicked early look at the 2020 U.S. elections. First, I assessed the field of Democrats seeking to challenge Republican President Donald Trump in 2020. Then I turned to the 2020 presidential election itself, pondering how Democrats would potentially fare against Trump.

Now I turn my attention to

  1. The 34 elections for United States Senate (“Senate”) to be held in 2020.
  2. The three gubernatorial elections to be held 2019 (Kentucky, Louisiana, Mississippi) and the 11 gubernatorial elections to be held in 2020.

My goal is primarily to provide the view from 30,000 feet: what the “fundamentals” in each race reveal about the overall partisan landscape—and what the likelihood is Democrats will have the Senate majority in January 2021 (and cut into the Republican advantage in governor’s mansions) As such, I only briefly discuss actual or potential candidates in these races, other than incumbents seeking reelection.

“Fundamentals” are simply the sum of three values:

  1. The state’s partisan lean, measured by my 3W-RDM (weighted[1] three-election average of the difference between a state’s Democratic [minus Republican] margin in a presidential election and the Democratic [minus Republican] margin in the total national vote in that election).
  2. The estimated effect of incumbency (incumbent office-holders tend to receive a higher percentage of the vote than an open-seat candidate of the same party).
  3. The national partisan lean, as measure by the “generic ballot” question (variations on “If the election for were held today, would you vote for the Democratic candidate, the Republican candidate, or some other candidate?”)

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Just bear with me as I explain how I estimated the effect of incumbency for Senate and gubernatorial elections. As usual, unless otherwise noted, election data come from Dave Liep’s indispensable Atlas of U.S. Presidential Elections.

Senate. I first calculated an “expected margin of victory”[2] for each Democratic Senate nominee in the 35 Senate elections in 2018[3], the 34 Senate elections in 2016[4] and the 35 Senate elections in 2014[5]: a state’s 3W-RDM plus the national Democratic margin (minus Republican percentage of all votes cast) in that year’s elections. Using three elections years guarantees a minimum of two Senate elections from each state. The margins for the three previous Senate election years are:

2014 = D-5.8%

2016 = D+0.9%

2018 = D+9.9%

Next, I subtracted each actual margin (Democratic minus Republican) from the “expected” margin. I then calculated three averages of these differences within each election year:

  1. Races with Democratic incumbents
  2. Races with Republican incumbents
  3. Open-seat races (where expected margin is for party currently holding the office)

Within each election year, then, the effect of incumbency for Democrats is simply the first average minus the third average[6], while the Republican advantage is the second average minus the third average[7]. And the estimated effect of incumbency for each party is the weighted average (2018=3, 2016=2, 2014=1) of the election-year averages.

For Democratic Senate incumbents, the effect is +4.4 percentage points (“points”), and for Republican Senate incumbents the effect is +2.6 points. Somewhat arbitrarily, I divide these values by 1.5 for incumbents who have won a special election, but not yet served a full six-year term and by 2.0 for incumbents who were appointed to the seat and have yet to face the voters.

Governor. Complicating these calculations is that five states hold their gubernatorial elections in odd-numbered years; thus, in November 2019, Kentucky, Louisiana and Mississippi will elect a governor, as will New Jersey and Virginia in November 2021.

As a result, I analyzed data from two-year cycles: 38 gubernatorial elections in each of 2017-18[8] and 2013-14[9], and 15 gubernatorial elections in each of 2015-16[10] and 2011-12[11]; going back to 2011 guarantees at least two gubernatorial elections from each state (with New Hampshire and Vermont, which hold gubernatorial elections every two years, included four times[12]). The calculations were otherwise the same, except for calculating a four-cycle weighted average (4,3,2,1)[13]: for Democratic gubernatorial incumbents, the effect is +5.7 points, and for Republican gubernatorial incumbents the effect is +8.5 points.

That the effect of incumbency is stronger for governors than for Senators reflects how partisan Senate elections have become.

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Let us now turn to the elections themselves. I base the “national lean” of D+6.0 on generic ballot polls listed on FiveThirtyEight.com, which have varied between D+2 and D+9—and mostly between D+5 and D+7—over the last few weeks. While this value is broadly in line with the last four Senate election years (weighted average=D+4.3 points; unweighted average from last two presidential election years= D+6.5), it is much higher than the last four gubernatorial election cycles (weighted average=D-0.6 points; unweighted average from last two presidential election years= D-3.2).

2020 Senate elections. Republicans currently hold 53 Senate seats, with 47 held by Democrats (including Independent Senators Angus King of Maine and Bernie Sanders of Vermont, who caucus with Democrats), meaning that to win back the majority in 2020, Democrats need either to win a net four seats, or win a net three seats and win the presidential election (Democratic Vice President would break 50-50 tie).

Table 1. 2020 Senate election overview

Name State Run

2020

3W-RDM INC Nat

Lean

Total Last margin First elected
DEMOCRATS
Edward Markey MA Yes 22.1 4.4 6.0 32.5 23.9% 2013
Jack Reed RI Yes 18.0 4.4 6.0 28.4 41.3% 1996
Richard Durbin IL Yes 14.7 4.4 6.0 25.1 14.6% 1996
Chris Coons DE Yes 12.5 4.4 6.0 22.9 13.6% 2010
Cory Booker NJ Yes 12.0 4.4 6.0 22.4 13.5% 2012
Jeff Merkley OR Yes 8.7 4.4 6.0 19.1 18.9% 2008
Tom Udall NM No 6.5 0.0 6.0 12.5 N/A
Gary Peters MI Yes 2.2 4.4 6.0 12.6 13.3% 2014
Mark Warner VA Yes 1.5 4.4 6.0 11.9 0.8% 2008
Tina Smith MN Yes 1.5 2.9 6.0 10.4 10.6% 2018
Jeanne Shaheen NH Yes 0.1 4.2 6.0 10.3 3.3% 2008
Doug Jones AL Yes -28.4 2.2 6.0 -20.2 1.7% 2017
 
REPUBLICANS
Susan Collins ME Yes 5.9 -2.4 6.0 9.5 37.0% 1996
Cory Gardner CO Yes 2.2 -2.4 6.0 5.8 1.9% 2014
Joni Ernst IA Yes -4.7 -2.4 6.0 -1.1 8.3% 2014
Thom Tillis NC Yes -6.0 -2.4 6.0 -2.4 1.6% 2014
David Perdue GA Yes -9.6 -2.4 6.0 -6.0 7.7% 2014
Martha McSally AZ Yes -9.7 -1.2 6.0 -4.9 Apptd 2019
John Cornyn TX Yes -15.3 -2.4 6.0 -11.7 27.2% 2002
Lindsey Graham SC Yes -15.7 -2.4 6.0 -12.1 15.5% 2002
Cindy Hyde-Smith MS Yes -18.5 -1.6 6.0 -14.1 7.3% 2018
Steve Daines MT Yes -18.6 -2.4 6.0 -15.0 17.7% 2014
Dan Sullivan AK Yes -19.2 -2.4 6.0 -15.6 2.1% 2014
Bill Cassidy LA Yes -22.2 -2.4 6.0 -18.6 11.9% 2014
Pat Roberts KS No -23.4 0.0 6.0 -17.4 N/A
Lamar Alexander TN No -25.8 0.0 6.0 -19.8 N/A
Ben Sasse NE Yes -25.8 -2.4 6.0 -22.2 32.8% 2014
Mike Rounds SD Yes -25.8 -2.4 6.0 -22.2 20.9% 2014
Tom Cotton AR Yes -28.2 -2.4 6.0 -24.6 17.1% 2014
Mitch McConnell KY Yes -28.7 -2.4 6.0 -25.1 15.5% 1984
James Risch ID Yes -34.2 -2.4 6.0 -30.6 30.7% 2008
Shelley Moore Capito WV Yes -35.5 -2.4 6.0 -31.9 27.7% 2014
James Inhofe OK Yes -38.1 -2.4 6.0 -34.5 39.5% 1994
Mike Enzi WY No -45.7 0 6.0 -39.7 N/A

At first glance, Democrats appear to have a significant advantage in the 2020 Senate elections (Table 1): of 34 Senate elections scheduled for November 2020, fully two-thirds (22) are currently Republican-held. And of those 22 seats, fully 73% (16) are potentially more vulnerable because they include…

Moreover, only one currently-Democratic seat appears particularly vulnerable as of now: Jones’ seat in deep-red Alabama (D-28.4); a reasonable estimate is that Jones would lose to a generic Republican by around 20 points. Even with the full effect of incumbency (+4.2), a repeat of Democrats’ strong overall performance in 2018 (D+9.9) and a pro-Democratic error of 5.4 points in 3W-RDM (the average miss over time), Jones would still be down about nine points to a generic Republican. Yes, Jones overcame similar odds in December 2017, but that was against a severely compromised Republican opponent.

And while first-term Democratic Senators Gary Peters of Michigan and Tina Smith of Minnesota (who won by double-digits in November 2018 after being appointed to replace Democrat Al Franken in December 2017) could be vulnerable—along with Jeanne Shaheen of New Hampshire and Mark Warner of Virginia, who narrowly won reelection in 2014—if Democrats only break even in 2020, as of now, they appear quite likely to prevail. They would join six safe Democratic incumbents (Ed Markey, Jack Reed, Richard Durbin, Chris Coons, Cory Booker[14] and Jeff Merkley) and a likely-safe open seat in New Mexico (with Democratic United States House of Representatives member [“Representative”] Ben Ray Luján a strong candidate to win the seat).

Ben Ray Lujan

2020 New Mexico Democratic Senate candidate Ben Ray Luján,

However, Democrats should not be banking on New York Senator Chuck Schumer switching from Minority to Majority Leader in January 2021 just yet. While as many as 16 Republican-held seats are arguably vulnerable, only two are in states that even lean Democratic: Maine (D+5.9) and Colorado (D+2.2). And while Gardner is clearly vulnerable (he underperformed by about four points in 2014, when he beat incumbent Democrat Mark Udall), even a slight improvement by Republicans in the total national Senate vote puts that seat at toss-up status, at best. And Collins has been winning statewide in Maine since 1996, including winning her fourth term by an eye-popping 37.0 points!

Plus, the next four most vulnerable Republican incumbents (all finishing their first term)—Ernst, Tillis, Perdue and McSally—represent states averaging 7.5 points more Republican than the nation as a whole; this is why even in a very good Democratic year the fundamentals have these races “toss-up” at best. Moreover, while it is true that Ernst, Tillis and Perdue won in 2014 by an average of just 5.9 points (with McSally losing by 2.3 points in 2018)—a hair over the overall Senate Republican that year—all four now have the modest added advantage of running as incumbents in lean-Republican states. And where Democrats have a strong candidate to run against McSally—former astronaut Mark Kelly, husband of former Representative Gabby Giffords (D-AZ)—other strong candidates such as former Iowa Governor (and Secretary of Agriculture) Tom Vilsack and former Georgia House Speaker Stacey Abrams have ruled out running for the Senate in 2020.

Mark Kelly

Left to right: former Representative Gabby Giffords and 2020 Democratic Senate candidate Mark Kelly

Abrams and Vilsack are not the only high-profile Democrats choosing not to challenge vulnerable incumbent Republican Senators. Former National Security Advisor Susan Rice will not challenge Collins, while former Colorado Governor John Hickenlooper is running for president in 2020 instead.

Beyond those six races, Democratic chances to flip seats only get slimmer. Former South Carolina Democratic Party chair Jaime Harrison is formally exploring a bid against Senator Lindsey Graham. And while former Representative Beto O’Rourke (D-TX; running for president) and Representative Joaquin Castro (D-TX) passed on a run, Air Force veteran Mary Jennings “MJ” Hegar, who came within 3 points of defeating incumbent Representative John Carter (D-TX) in 2018, plans to run against Senator John Cornyn. Even with Democrats winning nationally by six points, however, the fundamentals suggest both Harrison and Hegar begin their races down around 12 points.

Jaime Harrison

2020 South Carolina Senate Democratic candidate Jaime Harrison

MJ Hegar

2020 Texas Senate Democratic candidate MJ Hegar

Mississippi, meanwhile, will see a rematch between Espy and Hyde-Smith as she seeks a first full term. But while he came within about seven points of unseating her in 2018, this will be a tough Senate race for Democrats to win, as the fundamentals have him down by 15.1 points—similar to the Democratic position against first-term Senators Daines in Montana (where outgoing Democratic Governor Steve Bullock is apparently running for president instead) and Sullivan (who only defeated Democratic incumbent Mark Begich by 2.1 points in 2014) in Alaska.

Mike Espy.jpg

2020 Mississippi Democratic Senate candidate Mike Espy

That leaves 11 Republican-held Senate seats which average 30.3 points more Republican than the nation. Even with three open seats it is very difficult to see how Democrats flip any of them. One intriguing exception, however, could be in Kentucky, where Senate Majority Leader Mitch McConnell (quite unpopular at home) is seeking a seventh term; if Air Force veteran Amy McGrath (who, like Hegar, came within three points of defeating an incumbent Republican Representative in 2018—in this case Andy Barr) were to run, she may be able to overcome the fundamentals showing a generic Democrat down 25.1 points to McConnell.

The bottom line?

While there are several plausible paths for Democrats to win back a Senate majority in 2020…

  1. Win presidency; Jones win in Alabama; win Maine and Colorado and one of Iowa, North Carolina, Georgia, Arizona
  2. Win presidency; Jones lose in Alabama; win Maine and Colorado and two of Iowa, North Carolina, Georgia, Arizona
  3. Lose presidency; Jones win in Alabama; win Maine and Colorado and two of Iowa, North Carolina, Georgia, Arizona
  4. Lose presidency; Jones lose in Alabama; win Maine and Colorado and three of Iowa, North Carolina, Georgia, Arizona
  5. Any of 1-4 above but substituting wins in even more Republican states such as Texas, South Carolina, Mississippi, Alaska and Kentucky.

…a great deal would have to go just right for Democrats in each scenario. In fact, it is easy to foresee anything from Democrats net losing a handful of seats (Alabama and some combination of Michigan, Minnesota, New Hampshire and Virginia) to winning a clear majority (holding Alabama, sweeping the six most vulnerable states and maybe even picking off South Carolina and/or Texas and/or Mississippi and/or Kentucky) is possible.

The silver lining for Democrats, though, is that forcing Republicans to invest money, time and resources in states like Alabama, Alaska, Arizona, Georgia, Iowa, Kentucky, Mississippi, North Carolina, South Carolina and Texas makes it that much harder for them to beat Democratic incumbents in Michigan, Minnesota, New Hampshire and Virginia.

2019-20 Gubernatorial elections. Republicans currently occupy governor’s mansions in 27 states, with Democrats occupying the remaining 23.

Three gubernatorial elections will be held in 2019, all in southern states averaging 23.1 points more Republican than the nation (Table 2). The lone Democrat is John Bel Edwards of Louisiana, and while the fundamentals have him down to a generic Republican by 10.5 points, he is generally popular with voters in his state and thus more likely than not to win reelection. By contrast, the only Republican governor to seek reelection this year—Matt Bevin of Kentucky—is the least popular governor in the country; still, the fundamentals have him beating a generic Democrat by a whopping 31.2 points. As for the open seat in Mississippi, the fundamentals have a generic Republican defeating a generic Democrat by 12.5 points.

This means that the likeliest outcome is no net change in partisan control of governor’s mansions in 2019—though that could mean the parties switch control in Louisiana and Kentucky!

Table 2. 2019-20 Gubernatorial election overview

Name State Run

2019/ 2020

3W-RDM INC Nat

Lean

Total Last margin First elected
2019 DEMOCRATS
John Bel Edwards LA Yes -22.2 5.7 6.0 -10.5 12.2% 2015
2019 REPUBLICANS
Phil Bryant MS No -18.5 0.0 6.0 -12.5 N/A
Matt Bevin KY Yes -28.7 -8.5 6.0 -31.2 8.7% 2015
2020 DEMOCRATS
John Carney DE Yes 12.5 5.7 6.0 24.2 19.2% 2016
Jay Inslee WA No 12.1 0.0 6.0 18.1 N/A
Roy Cooper NC Yes -6.0 5.7 6.0 5.7 0.2% 2016
Steve Bullock MT No -18.6 0.0 6.0 -12.6 N/A
 
2020 REPUBLICANS
Phil Scott VT Yes 27.7 -8.5 6.0 25.2 14.9% 2016
Chris Sununu NH Yes 0.1 -8.5 6.0 -2.4 7.0% 2016
Eric Holcomb IN Yes -16.3 -8.5 6.0 -18.8 6.0% 2016
Mike Parson MO Yes -15.9 -4.3 6.0 -14.2 Succ 2018
James Justice WV Yes -35.5 -8.5 6.0 -38.0 6.8% 2016
Doug Burgum ND Yes -29.4 -8.5 6.0 -31.9 57.1% 2016
Gary Herbert UT No -33.1 0.0 6.0 -27.1 N/A

Looking ahead to 2020, two states currently governed by Democrats, Delaware and Washington, are all-but-certain to remain in Democratic hands, with Governor John Carney poised to reprise his nearly-20-point win in 2016 and a Democrat (state Attorney General Bob Ferguson?) heavily favored to succeed Governor Jay Inslee (running for president instead).

Equally certain to remain in Republican hands are West Virginia and North Dakota (where James Justice—who switched parties after winning as a Democrat in 2016—and Doug Burgum will seek reelection), as well as Utah, where Governor Gary Herbert is term-limited from seeking reelection.  The fundamentals in these states have Republicans ahead by 32.3 points over a generic Democrat.

That leaves six races which could be competitive—although Governors Eric Holcomb of Indiana and Mike Parson (who became governor in June 2018, following the resignation of Eric Greitens, just elected in 2016) of Missouri—are ahead in the fundamentals by 14-19 points.

North Carolina Governor Roy Cooper barely defeated Republican incumbent Pat McCrory in 2016, and while the fundamentals have him beating a generic Republican by 5.7 points, this race would be a pure toss-up in a neutral partisan environment. Montana is another story, though, with Bullock retiring after two terms (and 16 consecutive years of Democratic governors); the fundamentals suggest a generic Republican would win back the governor’s mansion in Helena by 12.6 points (and that is with Democrats winning by six points nationally).

That only leaves two New England Republican governors who just won reelection last year, but who the fundamentals see as highly vulnerable: Phil Scott, who won by nearly 15 points in deep-blue Vermont (D+27.7), and Chris Sununu, who “only” won by 7.0 points in swing-state New Hampshire. If they did not lose in 2018, though, it is unlikely (though not impossible) they will lose in 2020.

The bottom line?

As of May 2019, the 14 gubernatorial elections in 2019 and 2020 will most likely result in a net gain of 1 (with Republicans winning the open governor’s seat in Montana) governor’s mansion, expanding their overall lead to 28-22—but races this year in Kentucky and Louisiana, and next year in Indiana, Missouri, New Hampshire, North Carolina, and Vermont could yet surprise.

Until next time…

[1] The most recent election is weighted “3,” the 2nd-most recent election is weighted “2” and the 3rd-most recent election is weighted “1.”

[2] That is, relative to the Republican candidate. I excluded data from special elections such as the December 2017 Senate election in Alabama.

[3] For the California Senate election, I used the total votes for Democratic, Republican and all-other-party candidates in the June 5, 2018 “jungle primary.” For the Mississippi special Senate election, I used the results from the runoff election on November 27, 2018. For the Maine and Vermont Senate races, I counted as “Democratic” votes those cast for Independent Senators Angus King and Bernie Sanders, respectively, since each man caucuses with the Democrats (and there was no Democratic Senate nominee in Vermont); in Maine, I counted the Democratic votes as “other.” Notably, counting votes for King and Sanders as “other” (and Democratic votes in Maine as “Democratic”) only changes the national Democratic margin from +9.9 percentage points to +9.4.

[4] For the California Senate election, I used the total votes for Democratic, Republican and all-other-party candidates in the June 7, 2016 “jungle primary.” For the Louisiana Senate election, I used the results from the runoff election on December 10, 2016.

[5] I excluded the Alabama Senate race in which Republican incumbent Jeff Sessions ran unopposed.

[6] These values were +0.9% in 2018, +6.5% in 2016 and +10.6% in 2014.

[7] These values were +2.6% in 2018, +3.6% in 2016 and -0.7% in 2014.

[8] I counted the 2018 Alaska gubernatorial election as a Democratic open seat after Independent Governor Bill Walker suspended his reelection campaign on October 19, 2018, throwing his support to Democratic nominee Mark Begich.

[9] I counted Walker as a Democrat in 2014 Alaska gubernatorial election (though counting him as “Other” would have made little material difference). I counted the Rhode Island gubernatorial election as a Democratic open seat although outgoing Governor Lincoln Chafee was an Independent (who briefly sought the 2016 Democratic presidential nomination).

[10] For the 2015 Louisiana gubernatorial election, I used data from the runoff election held November 21, 2015.

[11] Because incumbent Republican governor Bobby Jindal easily cleared the 50% threshold on election day 2011, for the 2011 Louisiana gubernatorial election, I used the sum of all votes cast for the candidate of each political party (Republican, Democrat, Other) that day.

[12] West Virginia is counted three times because it also held a special gubernatorial election in 2011.

[13] Democratic incumbency “advantage” was +2.0% in 2017-18, +6.3% in 2015-16, +5.7% in 2013-14 and +18.9% in 2011-12; the corresponding Republican values were +17.3%, -3.4%, +10.3% and +5.1%.

[14] Or whoever replaces him, should he become the next president or vice president of the United States.

Organizing by themes I: American politics

This site benefits/suffers/both from consisting of posts about a wide range of topics, all linked under the amorphous heading “data-driven storytelling.”

In an attempt to impose some coherent structure, I am organizing related posts both chronologically and thematically.

Given that I have multiple degrees in political science, with an emphasis on American politics, it is not surprising that I have written a few dozen posts in that field…and that is where I begin.

I Voted sticker

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I started by writing about the 2016 elections, many based on my own state-partisanship metric (which I validate here).

The absurdity of the Democratic “blue wall” in the Electoral College

Hillary Clinton’s performance in five key states (IA, MI, OH, PA, WI)

Why Democrats should look to the south (east and west)

How having (or not) a college degree impacted voting

An alternative argument about gerrymandering

An early foray into what I call “Clinton derangement”

The only statistic from 2016 that really matters

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Here are a few posts about presidential polling (before FiveThirtyEight jumped on the bandwagon)…

Be careful interpreting President Trump’s approval polls

…and the 2017 special election in Georgia’s 6th Congressional District (GA-6)

Ossoff and the future of the Democratic Party

Using GA-6 polls to discuss statistical significance testing (spoiler: I am not a fan)

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And then I started looking ahead to 2018…first to control of the United States House of Representatives (“House”). Note that posts are often cross-generic…

An alternative argument about gerrymandering

The impact of voting to repeal (and not replace) Obamacare (May 2017)

I debut my simple forecast model (June 2017)

Making more points about polls and probability

A March 2018 update

A followup March 2018 update (after which I stopped writing about the 2018 House elections)

…then the United States Senate

The view from May 2017

What it meant that the Senate voted NOT to repeal Obamacare in July 2017

The view from December 2017

…and, finally, races for governor in 2017 AND 2018.

The view from June 2017

A tangentially-related post may be found here.

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After Labor Day 2018, I developed models (based on “fundamentals” and polls) to “forecast” the Senate elections…

September 4

September 13

October 23

…and those for governor (the October 23 post addressed both sets of races)

September 16

These culminated in…

My Election Day cheat sheet

And my own assessment of how I did (spoiler: not half bad)

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Beginning in April 2019, I turned my attention to the 2020 elections.

First came a wicked early look at the relative standings of the dozens of women and men actually or potentially seeking the 2020 Democratic presidential nomination:

April 2019

Then came a wicked early look at the 2020 presidential election itself.

April 2019

And, of course, a wicked early look at races for Senate (2020) and governor (2019-20).

With the first of regular updates to both the 2020 Democratic presidential nomination and the 2020 presidential election in May 2019

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Finally, there are other politics posts that defy easy categorization.

I indulged in some speculative alternative history about the presidential elections of 1948 and 2000.

I delineated issue differences between Democrats and Republicans.

I got a bit personal here and here, concluding with the fact that, despite overlapping in the same residential college at Yale for two years, I did NOT know Associate Justice Brett Kavanagh at all.

I argued for the abolition of the Electoral College.

Until next time…

2018 Election Cheat Sheet: How did I do?

I should apologize to our younger daughter’s friend’s mother.

In my…determination…to be settled in front of the television with snacks and beverages at precisely 6 pm EST on November 6, 2018, I might have been a bit abrupt collecting our youngest daughter from a local taqueria where said friend’s mother had generously taken them to supper (after schlepping them and one other girl back from gymnastics class).

However, thanks to help from the same daughter, I was at my post at the appointed time. Our youngest daughter even carefully picked out all of the red M&M’s (plain and peanut) from their decorative bowls. There were no red cashews to extract (but they were still delicious).

I also had a blue mechanical pencil to mark my 2018 Election Guide, as well as an entire 12-pack of unflavored Polar Seltzer cans sitting on the floor to my left (as the evening turned into midnight and beyond, the line of empty blue cans on the floor emanating from the carton grew longer and longer).

And sitting within reaching distance of my right arm was this colorful fowl.

IMG_4010

You know it is a celebration in our home when “the rooster” makes an appearance. Rather than ice water, however, this evening it was filled with blue lagoons—which my wife Nell still cannot decide more closely resembles Windex or Scope.

As the early returns from Indiana and Kentucky were being tabulated on MSNBC, however, a sinking feeling set in that I would not be drinking as much of this cocktail as I had anticipated. I remembered from 2008 that Indiana’s Democratic pockets report much later than its eastern-half Republican counties, but Democratic Senator Joe Donnelly was trailing by well over 20 percentage points in a race that both FiveThirtyEight.com and I had labeled “Lean Democratic.” (Republican Mike Braun would eventually defeat Donnelly by 5.9 percentage points [points]) And Democrat Amy McGrath was not faring as well in the early tallies from the 7th Congressional District (CD) in Kentucky against incumbent Republican Andy Barr as I had hoped. (McGrath would eventually lose by 3.2 points.)

When polls closed at 7 pm EST in Vermont and Virginia, MSNBC almost immediately projected wins in their respective United States Senate (Senate) races for Independent Bernie Sanders and Democratic Senator Tim Kaine—meaning that the first calls of the night were for men I had voted for in 2016 in completely different contexts—Sanders in the Massachusetts Democratic Presidential Primary and Kaine as the Democratic nominee for vice president.

That sinking feeling only grew worse as the FiveThirtyEight.com “live tracker” of Democrats’ chances of regaining control of the United States House of Representatives (House) dipped below 50% around 8:30 or so. Nell, worried, yelled into the living room, “I am not hearing any whoops or cheers.”

At just before 9 pm (when it was already clear Republicans would not only maintain control of the Senate but add seats), the indefatigable Steve Kornacki  announced NBC was giving the Democrats only a 65% chance of regaining the House, projecting they would finish with between 216 (2 too few) and 232 House seats; this translates to a net gain of between 21 and 37 seats.

Finally, however, as votes were counted in Virginia and, especially, New York, both the FiveThirtyEight.com tracker and the NBC “big board” manned brilliantly by Kornacki creeped higher and higher.  I do not remember when MSNBC projected Democrat Abigail Spanberger had defeated two-term Republican Dave Brat in Virginia’s 7th CD, but it was then I realized the anticipated “blue wave” (at least in the House) would materialize. When Democrat Max Rose beat two-term incumbent Republican Dan Donovan in New York’s 11th CD (on Republican-leaning Staten Island), it was off to the races.

Finally, at just before 11 pm EST, MSNBC (OK, I cannot find when they made their call, but it was likely within a few minutes of CNN) projected a Democratic takeover of the House.

A few minutes later, a not-yet-asleep Nell came downstairs to say that one of our politically-like-minded downstairs neighbors had texted her appreciation of my (partially-restrained) whooping-dancing “We got the House! We got the House!”

For the first time since the election of Republican Donald J. Trump as president of the United States, accompanied by a Republican House and Senate, plus a conservative-leaning Supreme Court, I truly exhaled.

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In my previous post, I laid out a series of “projected” final margins for 17 (of 35) Senate races and all 36 governor’s races. In this post, I described two simple models of the number of House seats Democrats would net in 2018 based upon the change from 2016 in the Democratic (vs. Republican) margin in the total vote cast nationwide for the House. In 2016, Democrats lost the total national House vote by 1.1 points (while netting 6 seats as they improved by 4.7 points from 2014).

Votes are still being tabulated across the country, especially in California, but enough time has passed since Election Day to see how my projections compared to the actual margins (and to the FiveThirtyEight.com assessment of those same races), starting with the House.

House. According to the indispensable Cook Political Report vote tracker, as of 6 pm EST on November 18, 2018, nearly 110.7 million votes had been cast in House races. For perspective, 81.0 million, 86.8 million and 78.8 million House votes were cast in the last three midterm elections (2006, 2010, 2014), respectively. And that total was 129.8 million in the last presidential election year (2016). (House election data from the Cook tracker and here).

Democrats have thus far won 53.0% of those votes, compared to 45.7% for Republicans (and 1.3% for a smattering of third-party candidates) for a Democratic margin of 7.7 points…and an 8.8-point shift towards the Democrats from 2016 (and 13.5 points from 2014!)

According to my preferred “simple” model (change in margin only), a shift of 8.8 points would yield a gain of 26 seats (and give Democrats a 72% chance of regaining House control). My “complex” model (accounting also for whether the election was a midterm or not) was more bullish on the net seat gain (30) but more bearish on the probability (64%). Averaging across the two models yields a net of 28 seats and a 68% probability of Democratic House control.

Meanwhile, FiveThirtyEight.com’s final House forecasts projected a Democratic national House margin of 9.2 points (the median of their Lite, Classic and Deluxe forecasts) and a net gain of 38 (ditto) seats. Using the FiveThirtyEight.com projected House margin ups my average projected House seat gains to 33 with an 82% chance of regaining control.

With three-seven House races yet to be called, the likeliest outcome is that Democrats will net 38 (36-41) House seats, widely geographically dispersed: six (with Republican David Valadao the likely winner in CD 21) in California; four each in New Jersey and Pennsylvania (+5 D, +1 R); three each in New York and Virginia; two each in Florida, Illinois, Iowa, Michigan and Texas; and one each in Arizona, Colorado, Georgia (with incumbent Republican Rob Woodall leading Democrat Carolyn Bourdeaux by just 419 votes[1]), Kansas, Maine, New Mexico (almost certainly), South Carolina and Washington. Incumbent Republican Mia Love also leads Ben McAdams by just 419 votes. Minnesota showed no net change as Democrats flipped the 2nd and 3rd CDs while Republicans flipped the 1st and  8th CDs.

Based on the information I had on the morning of Election Day, that is 5 (3-8) seats more than I projected Democrats to net, well below the average nine seats by which my models “missed” across 24 previous midterm elections—and consistent with my models underestimating gains/losses in “wave” elections.

FiveThirtyEight.com almost perfectly nailed the actual Democratic net gain of seats, though (as of this writing) they overestimated the Democratic national House margin by 1.5 points; historically, this is not an especially large difference.

Most fascinating, however, is that a net gain of 38 House seats would actually be one seat higher than the upper range of what NBC was projecting at 9 pm EST on Election Day. Vote counting may be laborious and require infinite patience, but it is ultimately rewarding.

Senate. Table 1 compares the actual margin (Democratic percentage of total vote minus Republican percentage of total vote) in 33 2018 U.S. Senate races; italicized states indicate Republican pickups while boldfaced states indicate Democratic pickups. I excluded California, where incumbent Democrat Dianne Feinstein beat fellow Democrat Kevin de Leon by 9.0 points, and the special election in Mississippi, where incumbent Republican Cindy Hyde-Smith will face Democrat Mike Espy in a November 27 runoff. The latter race should be an easy win for Hyde-Smith in ruby red Mississippi (18.5 points more Republican than the nation as a whole, according to my 3W-RDM), but Hyde-Smith’s recent comments may make this race closer than expected.

Table 1. Comparing projected to actual 2018 U.S. Senate election margins*

State 3W-RDM Actual Difference

(Projected – Actual)

AV Difference

(Projected – Actual)

JBWM 538.com JBWM 538.com
Hawaii 34.3 42.2 -11.2 11.2
Vermont 27.7 39.9 -1.3 1.3
Maryland 22.6 33.9 -3.3 3.3
Massachusetts 22.1 24.8 -1.3 1.3
New York 21.6 33.0 4.8 4.8
Rhode Island 18.0 23.0 -5.6 5.6
Connecticut 12.8 20.2 -1.2 1.2
Delaware 12.5 22.2 -4.7 4.7
Washington 12.1 17.0 -5.4 5.4
New Jersey 12.0 10.6 1.5 -0.9 1.5 0.9
New Mexico 6.5 23.5 5.3 5.3
Maine 5.9 19.0 -0.9 0.9
Michigan 2.2 6.6 -6.3 -4.6 6.3 4.6
Nevada 2.0 5.0 4.7 4.0 4.7 4.0
Virginia 1.5 16.0 0.2 0.2
Minnesota SE 1.5 10.6 1.4 1.0 1.4 1.0
Minnesota 1.5 24.1 2.7 2.7
Wisconsin 0.7 10.8 -0.8 -2.0 0.8 2.0
Pennsylvania -0.4 12.8 -2.0 1.3 2.0 1.3
Florida -3.4 -0.2 -2.2 -3.4 2.2 3.4
Ohio -5.8 6.4 -5.7 -5.0 5.7 5.0
Arizona -9.7 2.2 0.7 0.5 0.7 0.5
Texas -15.3 -2.6 3.2 1.9 3.2 1.9
Missouri -15.9 -6.0 -5.5 -7.0 5.5 7.0
Indiana -16.3 -5.9 -7.1 -9.6 7.1 9.6
Mississippi -18.5 -20.3 0.8 0.8
Montana -18.6 3.5 -0.2 -1.2 0.2 1.2
Tennessee -25.8 -10.8 -6.3 -5.4 6.3 5.4
Nebraska -25.8 -19.6 -4.7 4.7
North Dakota -29.4 -10.8 -2.4 -6.0 2.4 6.0
Utah -33.1 -32.2 -2.8 2.8
West Virginia -35.5 3.3 0.0 -4.2 0.0 4.2
Wyoming -45.7 -37.0 7.1 7.1
Average Difference

(all projected elections)

 

-1.7

 

-1.9

 

3.1

 

3.7

Average Difference

(both projections only)

 

-1.7

 

-2.5

 

3.1

 

3.6

      *Excluding California (two Democrats) and the special election in Mississippi (runoff

      November 27, 2018)

States are sorted from most-to-least Democratic, according to their 3W-RDM score. The table presents the numeric and absolute value of the difference between the actual and projected Democratic margins in each election for both JustBearWithMe (JBWM) and FiveThirtyEight.com. Two sets of averages are presented at the bottom of the table: one was calculated using every election projected (I only projected the 17 most “interesting” races, while FiveThirtyEight.com projected all 35) and one was calculated only using the 16 listed Senate elections projected by both JBWM and FiveThirtyEight.com.

With Democratic Senator Bill Nelson conceding to Republican Rick Scott in the Florida Senate race, and the runoff in Mississippi still likely to result in a Republican hold, Democrats appear to have lost a net of 2 Senate seats. Besides Florida, Republicans ousted Democratic incumbents in Indiana, Missouri and North Dakota; they also won hard-fought races in Tennessee and Texas. Democrats, however, beat incumbent Republican Dean Heller in Nevada and won the open seat in Arizona vacated by Republican Jeff Flake.

My final back-of-the-envelope estimate was a loss of 0.9 Senate seats, while the median final FiveThirtyEight.com projection was a loss of 0.5 Senate seats; this is at most a 1.5 seat underestimate, depending on what happens in Mississippi, though I was slightly closer to the actual outcome. Both projections “called” the Florida and Indiana Senate races wrong—while FiveThirtyEight.com called the Missouri Senate race wrong as well.

Both JBWM and FiveThirtyEight.com overestimated Democratic margins in a swath of states stretching from North Dakota (average 4.2 points) south and east to Florida (2.8); states in which both projections overestimated the Democratic margin by at least four points were Ohio (5.4, on average), Michigan (5.5), Tennessee (5.9), Missouri (6.3) and Indiana (8.4). FiveThirtyEight.com also underestimated Republican margins in solidly Democratic Delaware, Hawaii, Rhode Island and Washington, as well as in solidly Republican Nebraska.

At the same time, both projections underestimated Democratic margins in Nevada (4.4) and, to a lesser extent, Texas (2.7); FiveThirtyEight.com also significantly underestimated Democratic margins in New Mexico, New York and Wyoming.

Overall, I overestimated Democratic Senate race margins by an average of 1.7 points (3.1 points in absolute terms) while FiveThirtyEight.com missed by an average of 1.9 points (3.7 in absolute terms). Only looking at the 16 Senate races we jointly assessed, FiveThirtyEight.com’s performance is slightly worse: overestimating Democratic margins by 2.5 points (though just 3.6 in absolute terms). This suggests FiveThirtyEight.com performed slightly better in Senate races in which the winner was clear well in advance.

Governor. Table 2 compares the current actual margin (Democratic percentage of total vote minus Republican percentage of total vote) in 35 2018 gubernatorial elections; italicized states indicate Republican pickups while boldfaced states indicate Democratic pickups. I excluded Nebraska because no polls were conducted of its gubernatorial election. States are again sorted from most-to-least Democratic.

Table 2. Comparing projected to actual 2018 U.S. Gubernatorial election margins**

State 3W-RDM Actual Difference

(Projected – Actual)

AV Difference

(Projected – Actual)

JBWM 538.com JBWM 538.com
Hawaii 34.3 29.0 -4.1 -1.1 4.1 1.1
Vermont 27.7 -15.0 -10.0 -3.6 10.0 3.6
California 23.2 22.6 5.7 5.2 5.7 5.2
Maryland 22.6 -12.7 -8.7 4.9 8.7 4.9
Massachusetts 22.1 -32.6 -2.7 1.4 2.7 1.4
New York 21.6 22.2 0.5 3.1 0.5 3.1
Rhode Island 18.0 15.5 0.1 -4.9 0.1 4.9
Illinois 14.7 15.4 -2.4 6.1 2.4 6.1
Connecticut 12.8 3.2 -3.9 -1.9 3.9 1.9
Oregon 8.7 6.4 -3.0 -0.1 3.0 0.1
New Mexico 6.5 14.4 5.2 5.0 5.2 5.0
Maine 5.9 7.6 -1.8 -4.7 1.8 4.7
Colorado 2.2 10.6 1.9 -1.8 1.9 1.8
Michigan 2.2 9.5 0.5 -0.2 0.5 0.2
Nevada 2.0 4.1 2.9 3.9 2.9 3.9
Minnesota 1.5 11.5 2.7 1.4 2.7 1.4
Wisconsin 0.7 1.2 -2.9 -0.5 2.9 0.5
New Hampshire 0.1 -7.0 -0.8 1.3 0.8 1.3
Pennsylvania -0.4 16.8 0.2 1.4 0.2 1.4
Florida -3.4 -0.4 -4.3 -4.6 4.3 4.6
Iowa -4.7 -2.7 -4.3 -3.5 4.3 3.5
Ohio -5.8 -4.2 -5.4 -5.7 5.4 5.7
Georgia -9.6 -1.4 -0.4 0.8 0.4 0.8
Arizona -9.7 -14.2 -2.5 -0.5 2.5 0.5
Texas -15.3 -13.3 2.6 3.6 2.6 3.6
South Carolina -15.7 -8.0 4.7 5.6 4.7 5.6
Alaska -19.2 -7.9 -5.1 -3.9 5.1 3.9
Kansas -23.4 4.5 7.1 5.8 7.1 5.8
Tennessee -25.8 -21.1 -5.7 -7.5 5.7 7.5
South Dakota -25.8 -3.4 -2.5 -0.9 2.5 0.9
Arkansas -28.2 -33.5 -3.5 -6.1 3.5 6.1
Alabama -28.4 -19.2 1.6 -3.0 1.6 3.0
Idaho -34.2 -21.6 -3.4 -5.2 3.4 5.2
Oklahoma -38.1 -12.1 -2.3 -4.9 2.3 4.9
Wyoming -45.7 -39.8 -4.2 -9.8 4.2 9.8
Average Projected-Actual -1.4 -0.7 3.4 3.5

      **Excluding Nebraska because no polls were conducted of its gubernatorial election

With Democrats Andrew Gillum in Florida and Stacey Abrams (sort of) in Georgia conceding to Republicans Ron DeSantis and Brian Kemp, respectively, Democrats netted six governor’s mansions. Democrats defeated Republican incumbents in Illinois and Wisconsin and won Republican-held open seats in Kansas, Maine, Michigan, Nevada and New Mexico; Republican Mike Dunleavey beat Democrat Mark Begich to win the open Independent-held governor’s mansion in Alaska. At the same time, Republicans cut their losses by narrowly holding the governor’s mansions in Florida, Georgia, Iowa and Ohio.

My final back-of-the-envelope estimate was a Democratic net gain of 9.2 governor’s mansions, while the median final FiveThirtyEight.com projection was 8.2 governor’s mansions. Both projections incorrectly “called” the gubernatorial elections in Florida, Iowa and Ohio for the Democratic candidate while mistakenly projecting a win in Kansas by Republican Kris Kobach over Democrat Laura Kelly.

Both JBWM and FiveThirtyEight.com overestimated Democratic margins by at least three points in Iowa (3.9 points on average), Idaho (4.3), Alaska (4.5), Florida (4.5), Arkansas (4.8), Ohio (5.5), Tennessee (6.6), Vermont (6.8) and Wyoming (7.0)—and, to a lesser extent Connecticut (2.9); all but Vermont[2] are at least 3.4 points more Republican than the nation as a whole. However, both projections underestimated Democratic margins in Nevada (3.4), New Mexico (5.1), South Carolina (5.2), California (5.5) and Kansas (6.5)—and to a lesser extent Texas (3.1); I addressed the woes besetting Kansas Republicans here.

Overall, I overestimated Democratic gubernatorial election margins by an average of 1.4 points (3.4 points in absolute terms) while FiveThirtyEight.com did so by an average of just 0.7 points (3.5 in absolute terms). Clearly, while both forecasts were identical in terms of correct and incorrect “calls,” FiveThirtyEight.com did a better job of assessing election probabilities and final margins.

Summary. Across all 51 Senate and gubernatorial elections “projected” by both JBWM and FiveThirtyEight.com, my projections overestimated Democratic margins by 1.5 percentage points on average, only slightly worse than the FiveThirtyEight.com average overestimation of 1.3 points. This is almost exactly the latter’s overestimation of the total national House Democratic margin by, at most, 1.5 points, suggesting that the 2018 midterm electorate was slightly more Republican than pollsters estimated (though well within historic parameters). The average miss in either direction of 3.4-3.5 points was also well within the range of recent elections.

However, these averages mask wide variation in Democratic under- and over-performance. In races with both a Senate and a gubernatorial election, Democrats had the most disappointing showings in Florida, Ohio and, especially, Tennessee; they also underperformed in Senate races in mostly Democratic states and in gubernatorial elections in mostly Republican states. Underperformance in two traditional presidential swing states—Florida and Ohio—could be of some concern to Democrats as they try to unseat President Trump in 2020.

On the brighter side, states where Democrats overperformed—California, Nevada, New Mexico and Texas—are all in the southwest (as is Arizona, where Democrats won a Senate race for the first time since 1988), an area of the country trending sharply Democratic. The closer-than-expected race for governor in South Carolina plus very close losses for governor in Florida and Georgia may also herald improved Democratic prospects in the southeast.

Besides geography, did state partisanship determine which state electorates were more or less Democratic than anticipated? For FiveThirtyEight.com’s gubernatorial election projections, the answer is…maybe. The Pearson correlation[3] between a state’s 3W-RDM and its numeric difference in gubernatorial margin is +0.44, while for the absolute value of the difference it is -0.37, suggesting that the more Democratic the state, the more Democrats overperformed in that state’s race for governor, while missing less in absolute terms. However, this could simply be an artifact of FiveThirtyEight.com’s newly-minted methodology for projecting gubernatorial elections.

The bottom line. As of January 3, 2019, Democrats will control the U.S. House of Representatives—most likely by 31 seats—for the first time in eight years, despite slightly “underperforming” in the total national House vote (which they still won by nearly 8 points). Their net gain of ~38 seats is the highest Democratic total since the Watergate elections of 1974 (49). Moreover, turnout in House elections—nearly 111 million votes and counting—will be at least 35.2% higher than the average turnout in 2006, 2010 and 2014. Democrats did not regain the Senate—suffering disappointing losses in Florida, Indiana and Missouri (as well as Tennessee and Texas)—but by winning elections in two southwestern states (Arizona, Nevada), they held their losses to two (or one, if they pull off an upset in Mississippi in 18 days), ground they will almost certainly make up in 2020, when the map is more favorable to Democrats (or, at least, far less unfavorable). Finally, they netted six governor’s mansions (including holding on to win a closer-than-expected race in Connecticut), despite disappointing losses in Florida, Georgia, Iowa and Ohio. Democrats will control governor’s mansions in 23 states—the most since the 2008 elections—which have a combined 280 electoral votes, meaning more than half of the nation’s population will have a Democratic governor.

Do not let a few disappointing results fool you. The Democratic wave in 2018 was strong and wide.

Until next time…

[1] We actually know Ms. Bourdeaux’s sister from our younger daughter’s former ballet class; following our move, we also share a dog park.

[2] Vermont voters may not have wanted to tell pollsters—in just three public polls—they were unwilling to vote for transgendered Democratic nominee Christine Hallquist.

[3] A number from -1.0 to +1.0 indicating the strength of the linear relationship between two variables. Briefly, a positive correlation means that as one variable increases the other variable does the same (and vice versa), while a negative correlation means that as one variable increases the other variable decreases (and vice versa). A correlation of zero means there is no association at all.

Your 2018 Election Cheat Sheet

The 2018 midterm elections end today, November 6, 2018. If you are not one of the 36 million Americans who have already voted, PLEASE vote! Democracy is too precious not to participate, as is your right.

I voted early, so starting at 6 pm EST (when some polls close in Indiana and Kentucky), I will be parked in front of MSNBC with my family, ample snacks—and a pitcher of blue lagoons (minus the cherry—maybe blueberries instead?).

blue lagoons

I will also have the following cheat sheet to keep track of the returns as they are announced. This sheet has one side each for United States Senate (“Senate”) and United States governor’s races, sorted by when the last polling locations close in a state (some states cross time zones, meaning eastern polling locations close one hour earlier than western ones); Washington state conducts all of its balloting by mail, so I slotted it in between the 11 pm (EST) and midnight closings.

2018 Election Guide

The sheet lists the surnames of the Democratic and Republican (and occasional Independent) candidates in each race. Incumbents are underlined; the candidate of the party currently holding the seat is italicized. I also list two “projected” final vote margins for each race, one calculated by me (Just Bear With Me—JBWM) and one calculated by FiveThirtyEight.com (here and here); I did not calculate a margin for every Senate race. There is a column for the actual margin, plus columns for the difference between projected and actual margins. You can effectively ignore the Mississippi special election, which will almost certainly proceed to a November 27 runoff. I am curious how much better (or worse), on average, my methods will turn out to be compared to those designed by Nate Silver.

While I describe my algorithm (and each Senate race) here, with follow-ups here and  (plus details on each governor’s race) here, I made two recent alterations. First, all polls with a midpoint of October 25 or later are weighted twice as much as polls with a midpoint between September 1 and October 24. These latter polls, in turn, are weighted twice as much as polls with a midpoint of August 31 or earlier. Second, the calculation of how much polls are weighted over “fundamentals” now includes the number of polls conducted entirely in October or later.

Unlike FiveThirtyEight.com, I did not attempt to divine how undecided voters would vote; in essence, I assume (for better or worse) they will “break” the way decided voters did. To assess the impact of a systematic polling error in favor of one party or the other (averaging about 3.0 percentage points across the last four election cycles), you should add/subtract about 2.7 percentage points to the listed JBWM margin.

I colored seats projected to flip Democratic in blue and seats projected to flip Republican in red. I did not include the probability of a party winning each race, but (at least for the JBWM margins), you could think of any margin between +1.0 and-1.0 as a “toss-up,” any margin between 1.1 and 3.0 as “lean,” any margin between 3.1 and 6.0 as “likely,” any margin between 6.1 and 9.9 as “solid,” and any double-digit margin as “safe.”

By this method, in the Senate, there are two toss-up races: Missouri and Nevada, with the former leaning slightly Republican and the latter leaning slightly Democratic; I believe this is what will happen in those races. Arizona is likeliest to flip to the Democrats, while North Dakota is likeliest to flip to the Republicans. I thus call that the Senate breakdown will remain unchanged (using FiveThirtyEight’s margins, though, gives the Democrats a net gain of one seat, still one seat shy of a majority).

As for the governor’s races, I call a Democratic net gain of eight seats (Ohio, Florida, Illinois, Maine, Michigan, New Mexico, Wisconsin, Iowa and Nevada flipping Democratic, with Alaska flipping Republican), with South Dakota’s governor’s race a toss-up, leaning slightly Republican. FiveThirtyEight essentially agrees, though they are less certain about Iowa and Nevada.

But there are nine Senate and 10 governor’s races with a “JBWM” margin in the toss-up, lean or likely categories—meaning that there is still considerably uncertainty about how these races will end. This is one more reason that your vote is so vitally important.

Please vote, if you have not already!

Thank you!

And then sit back and track the returns on the cheat sheet with your company, snacks and beverages of choice.

Until next time…

A plea to readers with two weeks until Election Day 2018 ends…

The 2018 midterm elections end in two weeks, on November 6, 2018.

I write “end” because early voting is underway in 28 states, including Massachusetts. In fact, it opened Monday, October 22, and so I dragged our two daughters to Brookline Town Hall so they could participate in the process. And, yes, I voted straight Democratic with the exception of governor.

The best habits start early as our youngest daughter’s backpack reveals.

I Voted sticker.JPG

Along those lines—as a former political-scientist-in-training, lifelong political junkie and huge fan of democracy, I cannot strongly encourage you enough to vote.

Please.

This plea applies both to my American readers and to my many international readers, whenever the opportunity next presents itself.

**********

I do three things in this post.

  1. Update analyses of 2018 elections for the United States House of Representatives (“House”), United States Senate (“Senate”) and governor.
  2. Attempt to quantify the Republican polling “bounce” following the September 27, 2018 Senate Judiciary Committee testimony by Dr. Christine Blasey Ford and United States Court of Appeals Circuit Judge Brett M. Kavanaugh.
  3. Reconsider House, Senate and gubernatorial election projections under two scenarios: one where polls underestimate Republican voting by 3 percentage points, and where polls underestimate Democratic voting by 3 percentage points.

**********

Updated analyses. As of Tuesday afternoon, October 23, 2018, the FiveThirtyEight forecast was that Democrats would win the national House vote by 8.9 percentage points. According to my “simple” model, that translates to an 89.8% probability Democrats net at least the 23 House seats they need to regain control of the House (projecting a 29 seat gain). By comparison, the FiveThirtyEight forecast is 85.8% and 40 seats—reasonably close to my less “complex” estimates.

Since I last wrote about Senate races, I created two new metrics.

  1. A weighted probability of Democratic victory
  2. A projected Democratic election day margin.

The victory probability is simply a weighted average of the “fundamentals” and adjusted polling average (APA) probabilities, with the latter increasing in weight based upon the number, recency and quality of published polls. I estimate the “fundamentals” probability by assuming a normal distribution whose standard deviation is that of my 3W-RDM measure (4.9), and I estimate the APA probability using a margin of error derived from the total sample size of all polls of each election conducted entirely in calendar year 2018, to which I add 3.0 to account for recent average polling bias (averaging across the last four elections in the table “Polling bias shifts from election to election”).

Weights are calculated using this formula:

#Polls/10 + #Sept/Oct Polls/2 + (Average Pollster Rating – 4.3) + %Sept/Oct Polls/10

For example, 51 total polls have been conducted since January 1, 2018 in the Florida Senate race, with 21 conducted since September 1, with an average pollster rating of 2.7 (using the letter-grade assigned by FiveThirtyEight on a scale where A+=4.3, A=4.0, etc.). Thus, the amount by which polls are weighted over fundamentals in this race is 51/10 + 21/2 + (2.7-4.3) + 41.2/10 = 5.1 + 10.5 – 1.6 + 4.1=18.1.

The “projected Democratic margin” is also the weighted average of the “fundamentals” and APA margins.

Table 1: Democratic Victory Probabilities and Margins in 10 Key 2018 Senate Elections

State Probability Democratic Victory Projected Democratic Margin Democratic Gain, Hold, Loss 3W-RDM
AZ 90.3% D+2.5 Gain R+9.7
FL 70.2% D+1.3 Hold R+3.4
IN 72.8% D+1.2 Hold R+16.3
MO 38.9% R+0.4 Loss R+15.9
MT 92.4% D+4.1 Hold R+18.6
NV 43.6% R+0.2 Hold D+2.0
ND 0.2% R+7.3 Loss R+29.4
TN 19.2% R+2.7 Hold R+25.8
TX 0.1% R+6.2 Hold R+15.3
WV 90.4% D+5.1 Hold R+35.5
  Lose 0.8 seats R+0.3 R+1 R+16.8

The rough-and-ready forecasts in Table 1 are consistent with anything from a Democratic loss of one seat to a Democratic gain of one seat, depending on outcomes of very close races in Missouri and Nevada (not to mention Florida, Indiana and, perhaps, Tennessee). In this, they are broadly in agreement with the FiveThirtyEight Senate forecast (19.0% chance Democrats regain Senate; average loss 0.5 seats), though they are far more bullish on Democratic chances in Missouri (61.1%), North Dakota (30.1%), Tennessee (24.5%) and Texas (21.5%), and more bearish on Arizona (63.4%).

Not to belabor the point, but given the extreme “redness” of these 10 states (16.8 percentage points more Republican than the nation, on average), even a net loss of “only” one Senate seat would be a moral victory of sorts for Democrats…though a net gain of two or more seats would be an actual victory, in that they would then control the Senate.

Table 2: Democratic Victory Probabilities and Margins in 19 Key 2018 Gubernatorial Elections

State Probability Democratic Victory Projected Democratic Margin Democratic Gain, Hold, Loss 3W-RDM
AK 18.8% R+2.3 Loss R+19.2
AZ 1.5% R+8.6 Hold R+9.7
CO 99.8% D+9.0 Hold D+2.2
CT 100.0% D+9.0 Hold D+12.8
FL 99.4% D+4.6 Gain R+3.4
GA 38.2% R+0.2 Hold R+9.6
IL 100.0% D+16.5 Gain D+14.7
IA 95.5% D+2.7 Gain R+4.7
KS 31.4% R+2.0 Hold R+23.4
ME 100.0% D+6.8 Gain D+5.9
MI 99.9% D+9.7 Gain D+2.2
MN 99.8% D+8.7 Hold D+1.5
NV 53.3% D+0.9 Gain D+2.0
NM 100.0% D+8.6 Gain D+6.5
OH 28.2% R+0.3 Hold R+5.8
OK 0.5% R+6.8 Hold R+38.1
OR 100.0% D+7.9 Hold D+8.7
SD 23.6% R+4.4 Hold R+25.8
WI 99.1% D+5.0 Gain D+0.7
AVE Gain 7.9 seats D+3.4 D+7 R+4.3

Table 2 presents Democratic victory probabilities and margins for those gubernatorial elections most likely to change partisan hands and/or with margin< 10 percentage points. This group of states is far more purple, averaging only 4.3 points more Republican than the nation as a whole.

The governor’s race in Alaska altered considerably on October 19, when Independent Governor Bill Walker suspended his reelection campaign and endorsed Democrat Mark Begich over Republican Mike Dunleavy, though the likely outcome (a Dunleavy win) remains the same. Otherwise, Democrats remain strongly favored to pick up governor’s mansions in Florida, Illinois, Iowa, Maine, Michigan, New Mexico and Wisconsin, losing only in Alaska (Walker was effectively a Democrat). Extremely close races in Georgia, Nevada and Ohio could go either way, while Democrats are within shouting distance in Kansas and South Dakota (albeit, with only two polls). At the same time, once-possible pickups in Arizona and Oklahoma now seem far less likely.

The bottom line (again, in broad agreement with FiveThirtyEight) is that Democrats appear poised to net between six and nine governor’s mansions, putting them tantalizingly close to a majority.

A Kavanaugh bounce? There is evidence of a pro-Republican bounce in polling following the sequence of events between the Judiciary hearings on September 27 and the final confirmation vote (50-48 in favor) on October 6, including the week-long FBI investigation, spurred by increased Republican enthusiasm and voting likelihood.

To quantify the bounce, I compared Senate and gubernatorial race polls, unskewed and weighted by pollster rating, conducted before (though after August 1) and after September 27; all polls had to be completed by September 26 or started no earlier than September 27.

Table 3: 2018 Polling Data in 16 Key 2018 Senate Elections, Before and After Ford-Kavanaugh Hearings 

State Adjusted Poll Average

8/1-9/26

Adjusted Poll Average

9/27-10/22

Difference

(Pre-Post)

3W-RDM
AZ D+3.0 (11) D+0.3 (8) -2.8 R+9.7
FL D+0.3 (14) D+2.1 (10) +1.9 R+3.4
IN D+1.9 (3) D+0.2 (8) -1.6 R+16.3
MI D+14.7 (9) D+12.4 (3) -2.3 D+2.2
MN D+5.9 (4) D+10.1 (3) +4.2 D+1.5
MS R+13.5 (1) D+1.4 (1) -14.9 R+18.5
MO R+1.6 (7) R+0.8 (7) -0.8 R+15.9
MT D+5.2 (6) D+3.7 (1) -1.5 R+18.6
NV D+0.2 (5) R+1.6 (5) -1.8 D+2.0
NJ D+7.2 (2) D+6.9 (5) -0.3 D+12.0
ND R+4.6 (1) R+12.9 (2) -8.3 R+29.4
OH D+12.2 (6) D+16.5 (2) +4.3 R+5.8
PA D+15.3 (7) D+14.4 (1) -0.9 R+0.4
TN D+0.3 (8) R+6.2 (5) -6.5 R+25.8
TX R+3.2 (10) R+7.0 (7) -3.8 R+15.3
WV D+8.2 (7) D+7.9 (4) -0.3 R+35.5
WI D+7.9 (4) D+9.7 (2) +1.8 D+0.7
AVE D+4.4 D+2.4 -2.0 R+10.4

On average across 17 key Senate races (Table 3), the Republican position in the polls improved by an average of 2.0 percentage points following the Ford-Kavanaugh hearings. And the more Republican the state, the more the Republican candidate’s position improved (r=0.48)—as can be seen in Arizona, Mississippi, North Dakota, Tennessee and Texas (and also, surprisingly, in Democratic-leaning Michigan and Nevada). In fact, removing six states where the Democrat is strongly favored (albeit, four won by Republican presidential nominee Donald Trump in 2016; average 3W-RDM D+1.7), the Republican increase jumps to 3.7 percentage points (D+1.2 to R+2.6; r=0.31). At the same time, the bounce fades (-0.6; r=0.41) once you examine only states with at least two polls in both time periods.

Table 4: Polling Data in Selected 2018 Gubernatorial Elections, Before and After Ford-Kavanaugh Hearings

State Adjusted Poll Average

8/1-9/26

Adjusted Poll Average

9/27-10/19

Difference

(Pre-Post)

3W-RDM
AK R+0.9 (2) R+11.8 (2) -10.9 R+19.2
AZ R+6.5 (9) R+14.5 (6) -8.0 R+9.7
AR R+36.7 (1) R+37.7 (1) +1.0 R+28.2
CA D+10.6 (7) D+11.4 (4) +0.8 D+23.2
CO D+9.1 (2) D+7.5 (1) -1.6 D+2.2
CT D+8.5 (4) D+5.7 (3) -2.8 D+12.8
FL D+4.6 (13) D+4.7 (7) +0.1 R+3.4
GA D+1.9 (3) R+1.8 (6) -3.7 R+9.6
IL D+15.1 (4) D+17.6 (2) +2.5 R+16.3
KS R+0.4 (3) R+0.1 (1) +0.3 R+23.4
ME R+0.6 (1) D+7.8 (2) +8.4 D+5.9
MD R+16.9 (3) R+18.7 (2) -1.8 D+22.6
MA R+36.5 (2) R+38.8 (1) -2.3 D+22.1
MN D+6.9 (4) D+10.5 (3) +3.6 D+1.5
MI D+11.0 (8) D+11.2 (2) +0.1 D+2.2
NV D+2.1 (2) R+0.9 (4) -3.0 D+2.0
NH R+12.7 (2) R+13.7 (3) -1.0 D+0.1
NY D+1.0 (1) D+22.7 (2) +21.7 D+21.6
OH R+2.0 (5) D+1.3 (2) +3.3 R+5.8
OR D+7.0 (2) D+5.1 (1) -1.9 D+8.7
PA D+15.8 (6) D+11.4 (1) -4.4 R+0.4
RI D+7.3 (1) D+9.9 (2) +2.6 D+18.0
SC R+7.8 (2) R+23.7 (1) -15.9 R+15.7
TN R+14.5 (7) R+18.4 (3) -3.9 R+25.8
TX R+17.0 (8) R+20.1 (4) -3.1 R+15.3
WI D+3.3 (6) D+4.6 (2) +1.3 D+0.7
AVE R+1.8 R+2.6 -0.8 R+1.1

Alabama, Idaho, Iowa, New Mexico, Oklahoma have no polls after September 26

Hawaii had no polls between August 1 and September 26.

The trend was similar in 26 governor’s races (Table 4; average R+1.1)—an overall Republican increase of 0.8 percentage points, though once you remove New York (only one extreme outlier poll between August 1 and September 26), the increase becomes 1.7 percentage points. Again, the sharpest increases were in more Republican states (r=0.43), especially Alaska, Arizona, Georgia, South Carolina, Tennessee and Texas (and, surprisingly, in purple-to-blue Connecticut, Nevada and Pennsylvania). Examining only states with at least two polls in both time periods, the Republican increase jumps to 1.5 percentage points (r=0.36).

So, the “Kavanaugh bounce” appears to have been roughly one-to-three percentage points, and it was most evident among Republican voters in Republican states—who may well have been “coming home” to their party anyway (the Ford-Kavanaugh hearings may only have started the process earlier). And there is evidence the bounce is fading somewhat—at least in House voting (which covers the entire nation rather than a Republican-leaning set of states). The FiveThirtyEight House forecast dropped from an 80.7% chance of a Democratic takeover on September 30 to 73.9% on October 4—but then started to increase again October 9. Similarly, the forecast was a 32.0% chance of a Democratic Senate takeover on September 30, but by October 11 the probability had dropped to 18.6%. After rising three percentage points since then, as of Tuesday afternoon, October 23, it stood at 18.9%; the gubernatorial forecast does not lend itself to an analogous comparison.

Alternate polling scenarios. That even a small Kavanaugh “bounce” was enough to reduce Democratic Senate and gubernatorial gains by one-to-two seats shows how close this election (or, at least, the binary outcome of “majority/minority status”) is.

This can be shown by increasing—or decreasing–every polling margin by three percentage points, consistent with the statistical “bias” polls have displayed in the last four even-numbered election years; the direction of that bias changes from year to year.

For the House, if the projected national Democratic margin in total vote was actually 5.9% (that is, a 7.0% election-to-election increase), the probability they regain control plummets to 25%, with an average net gain of only 20 seats, three fewer than necessary. By contrast, however, were the margin 11.9%, Democrats would be locks to regain House control (99.6% probability), netting an average of 40 seats. Put simply, this close to Election Day, Democrats could still fall achingly short of a House majority—or net as many as 20 more seats than necessary.

For the Senate, a pro-Democratic polling bias of three percentage points in the polls would result in losing seats in Florida, Indiana, Missouri and North Dakota, while gaining zero seats; this is the nightmare scenario for Democrats. And while a pro-Republican polling bias of “only” two percentage points would mean winning in Arizona, that would still be a net loss of three Senate seats.

By the same token, a pro-Republican polling bias of three percentage points would almost certainly give them majority status in the Senate, as they still lose Heidi Heitkamp’s seat in North Dakota while winning seats in Arizona, Nevada and (possibly after a recount) Tennessee.

That is, this close to Election Day, a range of losing four Senate seats and gaining two seats remains plausible for Democrats.

Finally, in governor’s races, Democrats appear to be far enough ahead in key states that even a pro-Republican polling bias of three percentage points would still net them five governor’s mansions (win in Florida, Illinois, Maine, Michigan, New Mexico, Wisconsin; lose in Alaska) with Iowa a virtual tie. But a pro-Democratic polling bias of three percentage points would truly unleash a blue gubernatorial tsunami: not only would they likely WIN in Alaska (and Iowa), they would most likely add Georgia, Kansas, Nevada, Ohio, Oklahoma and South Dakota to their column. An historic net gain of 13 governor’s mansions could easily be in the offing.

**********

One overarching message from this barrage of data is that while pollsters do their best to model an unknown electorate and reduce uncertainty—the actual set of citizens who will turn out to vote remains, at best, a highly-educated guess and uncertainty (beyond just margin of error) still remains. Still, some good news for Democrats lies buried in a recent New York Times/Siena College poll. While the overall result was an eight percentage point lead for Republican Senator Ted Cruz (and among those whose certainty to vote is confirmed by prior voting behavior), Democratic challenger Beto O’Rourke actually LED by three percentage points among those who said they were almost certain to vote.

The other overarching message, then, is simply that every vote counts—even the tiniest changes in the composition of the 2018 electorate could fundamentally who governs us for the next two years.

I cannot say this often or loudly enough…PLEASE VOTE!

Until next time…

UPDATE: State of play in the 2018 Senate elections

Just as FiveThirtyEight.com released its Senate forecast, I update this post on the outlook for Democrats in the 36 elections for the United States Senate (“Senate”) this November 6 (and beyond, in the Mississippi special election). Feel free to compare and contrast the two.

To be more precise, I am updating the tables and a few paragraphs of text to reflect the following changes:

  1. FiveThirtyEight.com now projects Democrats to win the total vote of the United States House of Representatives (“House”) by 9.0 percentage points.
  2. Since Labor Day, a slew of new polls have been released.
  3. I corrected a flaw in how I weighted time and pollster ratings in the “adjusted pollster averages.”
  4. I now weight my adjusted polling average three times more than “fundamentals.”
  5. For the four Senate races in Table 4 and three Senate races listed as “Wildcards,” I now use the simple average margin in all polls released in 2018, as listed on that election’s Wikipedia page.
  6. I revised how I calculate incumbency advantage.

Just bear with me while I describe my Senate incumbency advantage calculation.

For each Senate election in 2012, 2014 and 2016, I calculated an “expected” outcome by adding the state’s partisan lean (3W-RDM) to the margin by which Democrats topped (or fell) to Republicans in the total national vote for Senate that year (D+0.9, D-5.8, D+12.1 percentage points in 2016, 2014, 2012, respectively). Next, I subtracted that from the actual Democratic margin in each race. I then calculated, for each election year, the average of these differences for the Senate races in which no incumbent sought reelection; open seats elections exemplify “generic Democrat” versus “generic Republican” elections. Next, I averaged the difference between each Democratic, and each Republican, incumbent’s “actual-minus-expected” margin and the open seat average for each of 2012, 2014, 2016. Finally, I took the simple average of these “incumbent-minus-open” differences, separately for Democratic and Republican incumbents, for each of the three year.

Using this new method, on average Democratic incumbency still adds 8.3 percentage points while Republican incumbency adds 9.6 percentage points.

Here is an example using 2016 data. On average, in the five open seat Senate elections that year, the Democratic-minus-Republican margin was 3.9 percentage points higher than would be expected based solely on partisan lean plus 0.9.  The actual margin for the seven Democratic incumbents averaged 10.4 percentage points (or 6.5 percentage points higher than the open seat average), and the actual margin for the 22 Republican incumbents averaged 7.5 percentage points (or 11.4 percentage points higher than the open seat average). Thus, in 2016 the Democratic and Republican incumbency advantages were 6.5 and 11.4 percentage points, respectively. The Democratic incumbency advantages in 2014 and 2012 were 9.8 and 8.5 percentage points, respectively, while for Republican incumbents the values were 1.1 and 16.5 points, respectively.

With that, here are the updated tables:

Table 1: Summary of 2018 Polling Data in 10 Key 2018 Senate Elections

State # Polls/ Pollsters Raw Margin Bias-Adjusted Margin Average Pollster Rating Adjusted

 Poll Average

Adjusted Pollster Average Final Ave
AZ 12/8 D+4.9 D+4.0/4.1 2.4/2.6 D+4.4 D+5.1 D+4.7
FL 31/16 D-0.2 D-0.7/-0.6 2.6/2.7 D-0.7 D-0.9 D-0.8
IN 4/4 D+3.8 D+2.4 2.3 D+5.3 D+5.3 D+5.3
MO 18/11 D-0.4 D-1.5/-0.8 2.4/2.6 D-1.0 D-0.7 D-0.9
MT 4/4 D+5.3 D+3.6 2.0 D+1.9 D+1.9 D+1.9
NV 9/5 D+2.7 D+1.1/0.7 2.5/2.3 D+1.2 D+1.2 D+1.2
ND 4/4 D-2.8 D-3.8 2.3 D-3.6 D-3.6 D-3.6
TN 15/11 D+0.8 D+0.1/-0.9 2.7/2.8 D+1.6 D+1.2 D+1.4
TX 17/13 D-6.1 D-6.1/-6.0 3.0/2.9 D-5.6 D-5.4 D-5.5
WV 10/10 D+8.2 D+7.2 2.6 D+6.9 D+6.9 D+6.9
AVE 12/9 D+1.6 D+0.6/0.5 2.5/2.5 D+1.0 D+1.1 D+1.1

Table 2: Most-endangered 2018 Democratic Senate incumbents

State Democrat Republican Expect WAPA Diff WTD
ND Heitkamp Cramer D-12.1 D-3.6 D+8.5 D-5.7
WV Manchin Morrisey D-18.2 D+6.9 D+25.1 D+0.6
MO McCaskill Hawley D+1.4 D-1.1 D-2.5 D-0.4
MT Tester Rosendale D-1.3 D+1.9 D+3.2 D+1.1
FL Nelson Scott D+9.4 D-0.8 D-10.2 D+1.8
IN Donnelly Braun D+1.0 D+5.3 D+4.3 D+4.2
AVE     D-3.3 D+1.4 D+4.8 D+0.3

 Table 3: Most-endangered 2018 Republican-held Senate seats

State Democrat Republican Expect WAPA Diff WTD
AZ Sinema McSally D-0.7 D+4.7 D+5.4 D+3.4
NV Rosen Heller D+1.5 D+1.2 D-0.3 D+1.3
TN Bredesen Blackburn D-16.8 D+1.4 D+18.2 D-3.1
TX O’Rourke Cruz D-15.8 D-5.5 D+10.3 D-8.1
AVE     D-7.9 D+0.5 D+8.4 D-1.6

Table 4: Once-endangered, now safe 2018 Democratic Senate seats

State Democrat Republican Expect Wiki Ave Diff WTD
WI Baldwin Vukmir D+18.0 D+11.1 D-9.4 D+12.8
OH Brown Renaccia D+11.5 D+10.2 D+4.5 D+10.5
PA Casey Barlettab D+16.9 D+13.7 D-1.5 D+14.3
MI Stabenow Jamesc D+19.5 D+17.6 D-1.6 D+18.0
AVE     D+16.4 D+13.2 D-3.3 D+14.0

Wildcards. New Jersey Democratic Senator Bob Menendez “should” be ahead of businessman Bob Hugin by 29.3 percentage points. However, Menendez “only” leads by an average of 10.0 percentage points in six 2018 polls—and just 6.0 percentage points in three July/August polls. The weighted average of these two percentages is 14.8 (11.8 using the three most recent polls), which is about where the race should ultimately land.

Minnesota Democratic Senator Tina Smith “should” be leading Republican State Senator Karin Housley by 14.6 percentage points; as an appointed senator, I arbitrarily cut her incumbency advantage in half. However, in an average of four polls released in 2018, Smith is ahead by “just” 8.4 percentage points; I currently anticipate Smith winning reelection by around the weighted average of 10.0 percentage points.

Appointed Mississippi Senator Cindy Hyde-Smith is very likely to face former Agriculture Secretary Mike Espy, a Democrat, in a November 27 runoff. Hyde-Smith would be expected to prevail over a generic Democrat by 14.2 percentage points, though in four head-to-head polls with Espy, she leads by “only” 7.3 percentage points (and 5.5 in the two most recent polls). The weighted averages suggest Hyde-Smith will prevail by 7.7-9.0 percentage points—though if this race ends up being decisive for Senate control, anything is possible.

nelson scott

The 2018 Florida Senate election between incumbent Democrat Bill Nelson (left) and Republican Governor Rick Scott is by far the most polled of all Senate races, and it could easily be the most expensive—and decisive for Senate control.

Bottom line. The likeliest outcomes are still between Democrats losing a net of two seats (flip Arizona; lose Nevada, North Dakota, Florida, Missouri) and gaining a net of one seat (flip Arizona, Nevada; lose North Dakota) with Tennessee and Texas JUST out of reach for Democrats. Still, there is a path for Democrats to recapture the Senate by starting with the D+1 seat outcome and winning any one of North Dakota, Tennessee and Texas.

Until next time…

2018 U.S. Senate elections: the state of play after Labor Day

I have written in broad terms (here and here) about the 36 United States Senate (“Senate”) races which will determine whether Democrats or Republicans control the Senate after the November 2018 midterm elections[1]. Including Independent Senators Angus King of Maine and Bernie Sanders of Vermont, Democrats control 49 seats; Republicans hold the remaining 51 seats (now that Arizona Governor Doug Ducey has appointed former Republican Senator John Kyl to fill the seat held by the late John McCain). To regain control (assuming Vice President Mike Pence, a Republican, would break a 50-50 tie), Democrats need to win a net of two seats on November 6, 2018. And while that sounds relatively easy, bear in mind that 27 of these seats are currently held by Democrats (including King and Sanders), with 10 of those seats in states Republican presidential nominee Donald Trump won in 2016, many by large margins.

In those previous posts, I described the political context of each Senate race (a variation on what the indispensable FiveThirtyEight.com calls “the fundamentals”) using three measures:

  1. State partisan lean (using 3W-RDM[2]): what you would expect the Democratic candidate minus Republican candidate margin would be if the national vote were split evenly between the two parties.
  2. Democratic advantage in the total national vote for United States House of Representatives [“House”]. As of September 4, 2018, FiveThirtyEight.com projects Democrats to win the national House vote by 8.4 percentage points, according to their “Classic” model.
  3. Incumbency. I calculate that, all else being equal, Democratic and Republican Senate incumbents garner 8.3 and 7.5 additional percentage points, respectively.

When I wrote those original posts, the identities of the Democratic and Republican Senate candidates were not yet known, and the polling sat between non-existent and irrelevant. Now, however, it is the day after Labor Day, the traditional starting point for American political campaigns. The field of candidates is effectively set in each state, and a slew of polls (of wildly-varying quality) have been conducted.

My goal here is to compare my “fundamentals” characterization to the actual polling to assess how the Democratic quest to recapture the Senate stands with (at most) nine weeks left to campaign. For 10 especially key races, I calculated a “weighted-adjusted polling average” (WAPA; current margin by which the Democrat leads/trails the Republican), otherwise I used the RealClearPolitics (RCP) average.

Just bear with me while I explain how I calculated WAPA.

First, I collected every poll released in 2018 listed on each race’s Wikipedia page [an exception to my preference to steer clear of Wikipedia]. For each margin I added/subtracted the pollster’s average partisan “bias” (how much, on average, a pollster’s results favor Democrats and Republicans compared to all other pollsters) listed in FiveThirtyEight.com’s pollster ratings. I then weighted each bias-corrected margin by a) how long prior to November 6 it was released (midpoint of days poll conducted[3] divided by 309, the number of days between January 1 and November 6) and b) the letter-grade rating assigned that pollster by FiveThirtyEight.com (on a scale where A+=4.3, A=4.0, A-=3.7, etc.; weights were numeric equivalent divided by 4.3) If a pollster was unlisted, I did not adjust for bias and followed FiveThirtyEight.com and assigned them a C+ rating.

However, because the “polls” WAPA treated all polls from the same pollster as “statistically independent” data points, I calculated a second WAPA for the six races (AZ, FL, MO, NV, TN, TX) in which at least one pollster released multiple polls in 2018. This “pollster” WAPA is the rating-weighted average of the time-weighted, unbiased average margin for each pollster. The final WAPA was the average of the two; only in Arizona and Texas did WAPA differ by two or more percentage points.

For the record, I did not adjust for “likely” vs. “registered” voters in these analyses. While the former tend to be slightly more Republican historically, I have not seen evidence they differ much this year, nor would it materially affect my conclusions.

Table 1: Summary of 2018 Polling Data in 10 Key 2018 Senate Elections

State # Polls/ Pollsters Raw Margin Bias-Adjusted Margin Average Pollster Rating Adjusted

 Poll Average

Adjusted Pollster Average Final Ave
AZ 9/7 D+6.6 D+5.4/5.5 2.4/2.7 D+6.8 D+3.9 D+5.3
FL 29/15 D-0.1 D-0.7/-0.4 2.5/2.7 D-0.6 D-0.5 D-0.5
IN 3/3 D+3.0 D+1.3 1.7 D+4.7 D+4.7 D+4.7
MO 18/11 D-0.4 D-1.5/-0.7 2.4/2.6 D-1.0 D-0.7 D-0.9
MT 4/4 D+5.3 D+3.6 2.0 D+1.9 D+1.9 D+1.9
NV 8/5 D+2.9 D+1.2 2.4/2.5 D+1.5 D+0.8 D+1.1
ND 4/4 D-2.8 D-3.8 2.3 D-3.6 D-3.6 D-3.6
TN 14/10 D+0.7 D-0.04 2.6/2.7 D+1.5 D+0.6 D+1.0
TX 15/11 D-6.4 D-6.6 3.0/2.9 D-6.1 D-4.1 D-5.1
WV 10/10 D+8.2 D+7.2 2.6 D+6.9 D+6.9 D+6.9
AVE 11/8 D+1.7 D+0.6 2.4/2.5 D+1.2 D+1.0 D+1.1

Before I summarize WAPA and compare them to the “fundamentals” in these 10 Senate races, I have observations about the polling itself (Table 1). One, publicly-available polls of these 10 Senate races have had a modest Democratic bias of about one percentage point. The bias is worst (D+1.7) in Indiana, Montana and Nevada, primarily due to the inclusion of at least one poll conducted by SurveyMonkey/Axios, whose polls have a pro-Democratic bias of 4.9 percentage points! Two, the overall quality of polling in these races has been…meh. The average poll within each of these races has been conducted by a pollster with a C+/B- rating. Again, much of this mediocrity can be ascribed to SurveyMonkey/Axios, which FiveThirtyEight.com assigns a D- rating; removing their polls entirely bumps the average rating to a more respectable B/B-. Three, while the Florida, Missouri, Tennessee and Texas Senate races have been polled 14 or more times in 2018, the Indiana, Montana and North Dakota have only been polled 11 times in total (by C-level pollsters, on average)—with no pollster polling the race more than once; the latter is also true of West Virginia, though it has at least been polled 10 times. Finally, only 32 (28.1%) of these 114 polls were conducted in July and August. Granted, polling is even more exceptionally tricky in the summer, when potential respondents are on vacation and/or tuned out of political news. But I still would love to see higher-quality pollsters like Marist, Monmouth and Quinnipiac conduct more surveys of these races soon.

**********

This analysis is divided into five parts:

  1. Safe seats
  2. Endangered Democratic incumbents
  3. Endangered Republican-held seats
  4. Once-endangered Democratic incumbents who appear safe
  5. Wildcards

Safe seats. The good news for Democrats is that 15 of the 27 Senate seats they are defending are safe: all 15 states were won in 2016 by Democratic presidential nominee Hillary Clinton, they average 14.8 percentage points more Democratic than the nation as a whole, and each features an incumbent running in what looks like an exceptional year for Democrats. And while I do not expect these 15 Democrats to win by an average of 14.8+8.4+8.3=31.5 percentage points, it would be a historic upset if any of these Senators lost.

And that includes two Senators, Amy Klobuchar of Minnesota and Tim Kaine of Virginia, whose states are “only” D+1.5. The “fundamentals” still say each should win by 18.2 percentage points; the RCP averages for these two races (D+22.0 and D+19.3, respectively) suggest they are beating expectations. Also, 2016 Libertarian presidential nominee Gary Johnson, the former two-term governor of New Mexico, recently entered that state’s Senate race between incumbent Democrat Martin Heinrich and Republican businessman Mick Rich as a Libertarian, introducing unexpected volatility. Still, in the five most recent polls, Heinrich leads his nearest opponent by about 14 percentage points, below the “expected” margin of 23.2 percentage points, but near-safe nonetheless.

Similarly, four currently Republican Senate seats—those currently held by Roger Wicker (MS), Deb Fischer (NE), Orrin Hatch (UT) and John Barrasso (WY) are certain to remain in Republican hands, even with Hatch’s retirement; 2012 Republican presidential nominee Mitt Romney is a near-lock to win that race.

Endangered Democratic incumbents. Six of the 10 Democratic incumbent Senators running in states Trump won appear vulnerable to varying degrees, according to Table 2. “WTD” is a weighted average of expected (0.33) and WAPA (0.67) margin, and it reflects a “best guess” (albeit with a wide “margin of error”) of what the final outcome will be on November 6; using no weights or weighting polls 3 times more than “fundamentals” does not substantively alter the conclusions.

With one exception, the polling is quite good for these six Democratic Senators, as they are beating expectations (mean=D-3.8) by 5.2 percentage points on average.

Table 2: Most-endangered 2018 Democratic Senate incumbents

State Democrat Republican Expect WAPA Diff WTD
ND Heitkamp Cramer D-12.7 D-3.6 D+9.1 D-6.6
WV Manchin Morrisey D-18.8 D+6.9 D+25.9 D-1.7
MO McCaskill Hawley D+0.8 D-0.9 D-1.5 D-0.3
MT Tester Rosendale D-1.9 D+1.9 D+3.8 D+0.6
FL Nelson Scott D+9.6 D-0.5 D-10.1 D+2.8
IN Donnelly Braun D+0.4 D+4.7 D+4.3 D+3.3
AVE     D-3.8 D+1.4 D+5.2 D-0.3

 First-term Democratic Senator Heidi Heitkamp, who won her first Senate race by 0.9 percentage points, currently appears headed for a mid-single-digits loss to North Dakota’s lone House member, Kevin Cramer. Granted, she is polling 9.1 percentage points better than expected, but that is not nearly enough to overcome North Dakota being R+29.4. Still, there are only three (excluding SurveyMonkey/Axios) polls of this race, and she beat expectations six years ago.

Heidi_heitkamp

North Dakota Senator Heidi Heitkamp

The good news, however, is that the other five Democratic incumbents are currently no worse than toss-ups.

The most surprising race on this list is Florida; eight months ago, I would have expected Ohio’s Sherrod Brown to be far more endangered. Running as a Democratic incumbent in slightly-Republican-leaning Florida (R+3.4), Bill Nelson “should” be ahead by about 13.1 percentage points (almost exactly his average in three previous races). Republican Governor Rick Scott has actually taken a slight polling lead (R+0.5), though, shifting from about 0.5 percentage points behind to 1.1 percentage points ahead starting in mid-June. As Scott is currently a statewide officeholder, I allotted him half of the 7.5 percentage point Republican incumbency advantage. Nelson “should” still win by 9.6 percentage points—and the weighted average projects a low single digits win for him on November 6.

Claire McCaskill of Missouri is also (slightly) underperforming expectations. The fundamentals make McCaskill the slightest of favorites (D+0.6), but she is currently trailing Missouri’s Attorney General Josh Hawley, a Republican, by 0.9 percentage points. And that average masks the fact she has lost ground since early June (when embattled Republican Governor Eric Greitens resigned, freeing Hawley from deciding whether to indict him), dropping from nearly-tied (R+0.2) to 1.4 percentage points behind. Still, this race is nearly a perfect toss-up (R+0.3).

Joe Donnelly of Indiana, by contrast, has taken a small polling lead (D+4.7) over Republican former State House member Mike Braun in what “should” be a coin flip (D+0.4). Caveat emptor: only been three polls have been conducted of this race (including one by SurveyMonkey/Axios), two showing Donnelly behind by an average 1.5 percentage points while the other has Donnelly ahead by 12 points! Still, a low single digits Donnelly win seems in the cards right now.

Finally, Montana’s Jon Tester and West Virginia’s Joe Manchin are considered by prognosticators to be in the “Lean Democratic” category, and I agree, even as the fundamentals and WAPA suggest caution. Tester should be losing to Montana’s Auditor, Matt Rosendale, by 1.9 percentage points, while West Virginia’s Attorney General, Patrick Morrisey, should be walloping Manchin by 18.8 percentage points! However, Tester’s narrow polling lead (D+1.9—in only four subpar polls) has him eking out a very narrow win. Manchin has a larger polling lead—D+6.9—but that still would have him losing by around two percentage points. Regardless, both men are proven winners in their states, and I think will both win in the mid-single-digits.

Bottom line: Democrats are likely to lose one, maybe two, of these six seats—an improvement over the five or six Republicans envisioned flipping just two years ago.

Endangered Republican-held seats. Four Republican-held Senate seats are in varying degrees of danger of being captured by strong Democratic opponents, according to Table 3: while Democrats should be losing these four seats by an average of 7.6 percentage points, they are slightly ahead in the polls overall.

Table 3: Most-endangered 2018 Republican-held Senate seats

State Democrat Republican Expect WAPA Diff WTD
AZ Sinema McSally D-1.3 D+5.3 D+6.6 D+3.1
NV Rosen Heller D+2.9 D+1.1 D-1.8 D+1.7
TN Bredesen Blackburn D-17.4 D+1.0 D+18.4 D-5.1
TX O’Rourke Cruz D-14.4 D-5.1 D+9.3 D-8.2
AVE     D-7.6 D+0.6 D+8.2 D-2.1

The retirement of Arizona Senator Jeff Flake, facing a tough reelection against Democratic House member Kyrsten Sinema, turned a toss-up into the Democrats’ best chance to flip a Republican-held seat; the caveat is that Republicans nominated their strongest general election candidate: House member Martha McSally. The fundamentals say McSally should win by about 1.3 percentage points, but Sinema has opened up a 5.3 percentage point lead in the polls; that lead has actually widened slightly since mid-June. A low-single-digits win for Sinema seems a good bet at this point.

kysten sinema

Arizona Senate candidate Kyrsten Sinema

The only Republican Senator seeking reelection in a state won by Clinton in 2016 is Nevada’s Dean Heller. The fundamentals back this up, suggesting he should lose to Democratic House member Jacky Rosen by about three percentage points. However, Rosen’s polling lead is “only” 1.1 percentage points, and Heller won reelection to a full term by 1.2 percentage points in 2012, even as Democrats won the national House vote by 1.3 percentage points. That said, this should be a far better year for Democrats, and Rosen seems set to win by a hair under two percentage points.

Jacky_Rosen

Nevada Senate candidate Jacky Rosen

When Tennessee Senator Bob Corker announced his retirement, what looked a possible 25 percentage point loss for Democrats became a little less uphill, even if the fundamentals still had Democrats down 17.4 percentage points. And when former two-term Democrat Governor Phil Bredesen entered the race against Republican House member Marsha Blackburn, the early polls showed a lead for the Democrat (D+4.1 through May 2018). However, since June, Blackburn has opened the narrowest of leads (R+0.4); overall, Bredesen leads by about one percentage ahead. Right now, that does not appear to be enough of a lead to overcome Tennessee being R+25.8, and I would expect Blackburn to win in the mid-single-digits.

Finally, Texas Senator Ted Cruz should be ahead by nearly 14.4 percentage points in this R+15.3 state. However, Democratic House member Beto O’Rourke has dramatically reduced that gap with eye-popping fundraising and relentless campaigning. I have suggested Texas could soon be fertile ground for Democrats, and O’Rourke’s (relative) success appears to bear that out. Nonetheless, O’Rourke still trails Cruz by about five points, though this obscures that the gap has dropped from 8.4 percentage points through early July to 3.5 percentage points since then. Overall, I would expect Cruz to win in the high single digits—though Democrats could win a victory of sorts if they force Republicans to invest time and money helping Cruz rather than in vulnerable House races.

Bottom line: Democrats could easily win two of these four seats, with Tennessee and Texas tantalizingly just out of reach.

Once-endangered Democratic incumbents who appear safe. The other four Democratic incumbents representing states won by Trump in 2016, Wisconsin’s Tammy Baldwin, Brown, Pennsylvania’s Bob Casey and Michigan’s Debbie Stabenow, appear headed for an average win of 14.5 percentage points (using RCP averages), nearly their average “expected” win of 15.9 percentage points (Table 4). Baldwin, who will face State Senator Leah Vukmir, is polling under 10 percentage points (8.0).

Table 4: Once-endangered, now safe 2018 Democratic Senate seats

State Democrat Republican Expect RCP Diff WTD
WI Baldwin Vukmir D+17.4 D+8.0 D-9.4 D+11.1
OH Brown Renaccia D+10.9 D+15.4 D+4.5 D+13.9
PA Casey Barlettab D+16.3 D+14.8 D-1.5 D+15.3
MI Stabenow Jamesc D+18.9 D+17.3 D-1.6 D+17.8
AVE     D+15.9 D+13.9 D-2.0 D+14.5

            a House member James Renacci

              b House member Lou Barletta

              c Businessman John James

Bottom line: These four swing states—three of which Trump won very narrowly—appear to be swinging solidly back toward the Democrats.

Wildcards. Three Senate races—two featuring appointed incumbents—are not (yet) in danger of changing hands, but each could still be interesting.

The fundamentals suggest New Jersey Democratic Senator Bob Menendez—in line to chair the powerful Foreign Relations Committee should Democrats recapture the Senate—should be ahead by a whopping 28.7 percentage points. However, the most recent RCP average has Menendez defeating businessman Bob Hugin by “only” 8.3 percentage points (three recent polls show an even closer race). This is almost certainly because Menendez was tried in 2017 on corruption charges, only to have a hung jury. While U.S. District Court Judge Jose Linares ultimately dismissed all the charges, they appear to have cost Menendez more than 20 percentage points of “expected” support. That is still not enough to overcome New Jersey’s strong partisan lean (D+12.0), however, and I currently anticipate Menendez winning by 10-15 percentage points.

When Minnesota Democratic Senator Al Franken resigned following allegations by numerous women of unwanted kissing and touching, Governor Mark Dayton appointed Democratic Lieutenant Governor Tina Smith to fill the seat. Smith will face reelection this November against Republican State Senator Karin Housley. Because Smith has only served in the Senate since January I (arbitrarily) cut her incumbency “advantage” in half, though the fundamentals still have her winning by 14.1 percentage points. However, the RCP average “only” has Smith ahead by 8.4 percentage points; perhaps voters hold Franken’s misdeeds against her. Nonetheless, I currently anticipate Smith winning reelection by around 10 percentage points.

And…the special election in Mississippi could decide Senate control—in late November. When Republican Senator Thad Cochran resigned for health reasons, Mississippi Governor Phil Bryant appointed Mississippi’s Commissioner of Agriculture and Commerce Cindy Hyde-Smith, a Republican, to fill the seat, making her the first-ever female Senator from Mississippi. Hyde-Smith will run for reelection on November 6 in a non-partisan (i.e., no party labels appear on the ballot) “open primary” against two opponents: Republican State Senator Chris McDaniel and former Agriculture Secretary Mike Espy, a Democrat. If no candidate tops 50% of the vote, a runoff election between the top two finishers—which polls suggest would be Hyde-Smith (simple average=31.2%) and Espy (28.5%), with McDaniel (16.8%) trailing well behind—would be held on November 27, 2018. The fundamentals suggest that a quasi-incumbent Republican Senator should beat a Democrat in Mississippi by 14.1 percentage points, though Espy could certainly make that closer. Still, this race is most likely to be an asterisk—easily remaining Republican—rather than a game-changer.

Bottom line: These three Senate races are intriguing, but the partisan gravity of these states makes it very unlikely any will change partisan hands.

Conclusion. Out of 36 Senate races, only 17 (18, counting New Mexico) are even remotely interesting, and only 10 of them are more than slightly likely to change partisan hands, based on each race’s “fundamentals” (partisan lean, Democratic wave, incumbency) and the current weighted-adjusted polling averages. As of September 4, 2018, Democrats seem likely to lose a Senate seat in North Dakota; retain four vulnerable seats (barely) in Florida, Indiana, Montana and West Virginia; and face genuine uncertainty in Missouri. They also seem likely to flip seats in Arizona and Nevada while falling short in Tennessee and Texas.

Overall—and with all necessary warnings about polling accuracy, unforeseen events and margins of error—Democrats appear poised either to net one Senate seat or to break even, depending on what happens in Missouri. This is NOT a prediction, merely a “best guess” based on available evidence: a net Democratic loss of one or two seats (or a gain of two or three seats) is certainly possible and would still put Democrats in an excellent position to regain Senate control in 2020.

Until next time…

[1] In previous posts, Republican Senator Thad Cochran of Mississippi had not yet resigned from the Senate.

[2] A weighted average (2008=16.7%, 2012=33.3%,2016=50%) of the difference between two measures: the state-level and national margins between the Democratic and Republican percentages of the total state/national vote.

[3] If the mid-point fell between two days, I used the later day. For example, if a poll was conducted between May 24 and May 29, the mid-point would between May 26 and May 27, meaning I would May 27.