The Republican advantage in the Electoral College is real

As I detail here, the Electoral College (“EC”), not direct popular vote, determines who wins American presidential elections. Since 1856, the first presidential election in which the two major candidates were a Democrat (James Buchanan) and Republican (John C. Fremont), there were four presidential elections in which one candidate won the EC while another candidate won the popular vote; in all four elections—1876, 1888, 2000, 2016—the Republican won the EC and, thus, the presidency.

Those elections—just four out of 41 (10%)—could be considered flukes, were it not for the fact Republicans maintain a clear, quantifiable advantage in the EC.

One way to think about this is to consider a presidential election in which the two major-party candidates receive exactly the same number of popular votes. Put another way, this is a situation where the difference between the Democratic percentage of the popular vote and the Republican percentage of the popular vote equals 0.0%.

If there was no partisan advantage in the EC, we would expect both candidates to receive 269 electoral votes (“EV”), exactly half of the 538 available to them. Or, at least, a number very close to 269, allowing for third-party candidacies and “faithless” electors who vote for someone other than the plurality winner of their state.

Table 1 lists the winner, political party, popular vote margin (Democratic % – Republican %) and number of EV won by the winning candidate for the 17 presidential elections from 1952 through 2016. I chose 1952 because it was the first presidential election to feature television commercials by the major candidates and televised nomination conventions. It is also the first election to show cracks in the previously solid Democratic south: Republican Dwight D. Eisenhower won Florida, Tennessee, Texas and Virginia in 1952, adding Kentucky and Louisiana in 1956. As usual, all elections data come from Dave Leip’s indispensable Atlas of U.S. Presidential Elections.

Table 1: Winning Presidential Party, Margin of Victory (Dem % – GOP %) and Electoral Votes Won: 1952-2016

Year	Electoral College Winner	Party	Margin	EV
1952	Eisenhower	Republican	-10.9%	442
1956	Eisenhower	Republican	-15.4%	457
1960	Kennedy	Democratic	0.2%	303
1964	Johnson	Democratic	22.6%	486
1968	Nixon	Republican	-0.7%	301
1972	Nixon	Republican	-23.1%	520
1976	Carter	Democratic	2.1%	297
1980	Reagan	Republican	-9.7%	489
1984	Reagan	Republican	-18.2%	525
1988	GHW Bush	Republican	-7.7%	426
1992	B Clinton	Democratic	5.6%	370
1996	B Clinton	Democratic	8.5%	379
2000	GW Bush	Republican	-0.5%	271
2004	GW Bush	Republican	-2.5%	286
2008	Obama	Democratic	7.3%	365
2012	Obama	Democratic	3.9%	332
2016	Trump	Republican	-2.1%	304

Republicans won 10 of these elections, by an average margin of 8.6% in the popular vote and 393.9 EV; this includes 2000 and 2016, when Democrats Al Gore and Hillary Clinton, respectively, won the popular vote but lost the EC. Democrats, meanwhile, won seven of these elections by an average margin of 7.1% and 361.7 EV.

In three elections, the Democratic and Republican percentages of the popular vote differed by less than one percentage point (“point”): 1960, when Democrat John F. Kennedy won by 0.2% with 303 EV; 1968, when Republican Richard M. Nixon won by 0.7% with 301 EV, with 13.5% and 46 EV for American Independent nominee George Wallace; and 2000, when Republican George W. Bush lost by 0.5%, but still eked out 271 EV after a controversial recount in Florida.

It is difficult to discern any sort of pattern here, other than the higher the popular vote margin, the more EV you win. Figure 1 shows this clearly.

Figure 1: Popular Vote Win Margin and Electoral Votes Won, 1952-2016

As expected, there is a strong linear association between popular vote margin and EV won—including 2000 and 2016; margin alone accounts for 86% of the variance in EV. The formula was calculated using ordinary least squares (“OLS”) regression, and it tells us the average number of EV one would expect a presidential candidate to win based upon their popular vote margin.

Thus, for every 1.0-point increase in popular vote margin (expressed as 0.01), that candidate wins an 11.1 additional EV, on average. Moreover, when the margin is 0.0 points—a popular vote tie—the winner should receive 292 EV, 23 more than the expected 269 or so. Also, to earn 270 EV, the winner would actually LOSE the popular vote by 2.0 points!

How is this possible?

Figures 2 and 3, which break down the popular vote margin-EV association by party, help to explain.

Figure 2: Popular Vote Margin and Electoral Votes Won: Democratic Presidential Candidates, 1952-2016

Figure 3: Popular Vote Margin and Electoral Votes Won: Republican Presidential Candidates, 1952-2016

For both major political parties, every 1.0-point in popular vote margin increases EV earned by an average of 12.3. And in both models, popular vote margin alone accounts for 92% of variance in EV; these two variables are VERY strongly linearly associated.

However, it is where the fitted line crosses the Y axis that makes all the difference—this is the expected EV won by each political party in the event of a tied popular vote. For Democrats, a tie equates to only 251.0 EV, on average, 19 fewer than needed to win the presidency. For Republicans, however, that same tie equates to 282.7 EV, 12.7 more than needed to win the presidency. The slopes and r-squared values are identical, the Republican line is just 31.7 points higher at every value of popular vote margin.

In other words, on average, a tied total popular vote translates to a 283-251 Republican win in the Electoral College, with 4 EV going to third-party candidates or otherwise up for grabs. That translates to a 32-EV Republican advantage in the Electoral College.

Another way to measure Republican advantage is to calculate what popular vote margin a presidential candidate needs, on average, to secure 270 EV. For the Democratic presidential nominee, the formula is:

Popular Vote Margin = (270 – 251.0) / 1233.1) = = +1.5%

And for the Republican presidential nominee, the formula is:

Popular Vote Margin = (270 – 282.7) / 1230.8) = = -1.0%

That is, a Democratic presidential nominee must win the national popular vote by at least 1.5 points to secure a minimum 270 votes, while a Republican presidential nominee can do so while losing the total popular vote by 1.0 points. Third-party EV and faithless electors keep the values from being identical. Still, that translates to a 2.5-point popular vote advantage for Republicans in the Electoral College!

This is a very robust finding. For example, while the 2016 election looks like an outlier—as does, to be fair, 1980, when Republican Ronald Reagan converted a 9.7-point popular vote margin of victory into 489 EV—removing it only improves the Democratic position slightly: a tied total popular vote still gives the Republican a 279.4 to 254.1 EC victory, while only reducing the popular vote advantage to 2.1 points.

Also, starting in 1964—the first election in which Alaska, Hawaii and the District of Columbia all contributed EV—actually increases the Republican advantage. The latter nominee would win 286.4 to 248.5 if the total popular vote were tied nationally, a 37.9 EV advantage equivalent to winning Texas’ 38 EV. Moreover, since 1964, a Democrat would need to win nationally by 1.8 points, on average, to win 270 EV, while a Republican could lose by 1.3 points—a gap of 3.1 points!

**********

My analysis of national- and state-level polling suggests 2020 Democratic presidential nominee Joseph R. Biden, Jr. currently leads Republican President Donald J. Trump by 7.5 points, up slightly from the last time I wrote about the state of the race.

Plugging 0.075 into the Democratic formula yields a projected EV total of 343.5. This is remarkably close to the 349.6 EV I estimate Biden will received based on in my model; the number increases to 352 if I simply count up the EV from states I calculate Biden has >50% chance to win.

I also assess Biden’s chances if all polls are systematically over-estimating Democratic strength by 3 points and if all polls are systematically under-estimating Democratic strength by 3 points. That is, I consider a universe in which Biden is actually ahead by 4.5 points or by 10.5 points.

Entering 0.045 into the Democratic formula yields an expected 306.5 EV—basically, the states won by Clinton in 2016 plus Michigan, Pennsylvania, Wisconsin and Florida. My estimate of Biden’s EV in this scenario is 301.7, or 308 using the states where Biden is better than even money.

Entering 0.105 into the Democratic formula yields an expected 380.5 EV—basically, the previous scenario plus Arizona, North Carolina, Ohio, Georgia and Iowa…but not Texas. The polling data, however, suggest Biden would do even better—389.6 EV, or 412 using the states where Biden is better than even money, including a 57.6% chance of winning Texas.

In other words, results from this simple one-variable model align almost exactly with the state of the race based on available polling data.

**********

Why this is the case, however, is a far more complicated question. The most direct answer is that Democratic votes are distributed less efficiently than Republican votes across the states. Democrats routinely win large states like California, New York and Illinois—104 total EV—by double-digit margins, padding their national vote total while adding 0 EV. Republicans, by contrast, win larger states by narrower margins, as they did in 2016, and smaller states like Wyoming, Idaho and Utah by huge margins which only minimally impact their national vote total.

Put differently, the Democratic strategy to run up the popular vote paradoxically hurts them in the Electoral College, while Republican strategy to eschew large national vote totals in favor of narrower wins in key states boosts them.

On a related note, Republicans have an advantage in swing states, as my 3W-RDMdemonstrates; this is a measure of how Democratic a state votes relative to the nation. Based solely on this measure, Table 2 lists how I would anticipate the following states to vote if Biden and Trump exactly tied in the total popular vote:

Table 2: Expected 2020 vote margins in 18 key states, based on tied popular vote

State	EV	3W-RDM	Current Biden polling
Oregon	7	8.7	n/a
New Mexico	5	6.5	11.3
Maine	4	5.9	10.4
Michigan	16	2.2	7.1
Colorado	9	2.2	12.4
Nevada	6	2.0	3.5
Minnesota	10	1.5	8.1
Virginia	13	1.5	9.6
Wisconsin	10	0.7	4.6
New Hampshire	4	0.1	5.2
Pennsylvania	20	-0.4	5.2
Florida	29	-3.4	3.9
Iowa	6	-4.7	-1.7
Ohio	18	-5.8	0.7
North Carolina	15	-6.0	2.0
Georgia	16	-9.6	-0.5
Arizona	11	-9.7	2.7
Texas	38	-15.3	-2.0

Assuming Biden starts with 175 EV[1] and Trump starts with 126 EV,[2] that leaves 237 EV up for grabs. In this popular-vote-tie scenario, Biden wins 84 of those EV, though Wisconsin and New Hampshire could be looking at a recount, for 259 EV. Trump wins the remaining 153 EV, with a recount possible in Pennsylvania, for 279 EV, very close to the 283-251 EV margin estimated earlier.

But while in this scenario Biden would narrowly win states like Michigan, Colorado, Nevada, Minnesota and Virginia—Trump would be looking at far easier wins in Florida, Iowa, Ohio, North Carolina, Georgia, Arizona and, especially, Texas. This is because of the enormous gap between Pennsylvania, at 0.4 points more Republican, and Florida, at 3.4 points more Republican. While a Democrat could theoretically win 279 EV—and the White House—by winning the total popular vote by 0.4 points, s/he would have to win by at least 3.4 points nationally to have a little breathing room.

That all said, Biden’s current estimated lead of 7.5 points gets him those 308 EV relatively easily, while making him slightly favored in Arizona and North Carolina, perched on the razor’s edge in Ohio and Georgia, and pounding on the door in Iowa and Texas. A slight polling error in his favor, strong Democratic turnout/depressed Republican turnout and a decisive win among late-deciding voters, and Biden could turn 343-352 EV into 412 EV.

When you know in advance how high the mountain you need to climb is, it is far easier to prepare to climb it.

Until next time…please stay safe and healthy…

[1] District of Columbia, Hawaii, Vermont, California, Maryland, Massachusetts, New York, Rhode Island, Illinois, Connecticut, Delaware, Washington, New Jersey

[2] South Carolina, Missouri, Indiana, Mississippi, Montana, Alaska, Louisiana, Kansas, Nebraska, South Dakota, Tennessee, Arkansas, Alabama, Kentucky, North Dakota, Utah, Idaho, West Virginia, Oklahoma, Wyoming