In recent weeks there has been considerable attention to proposals by some Republican politicians to change the allocation of presidential electoral votes from statewide winner-take-all to congressional districts–at least in states where doing so would help Republicans. If this method had been used for all electoral votes in presidential contests from 1968 to 2008, what would its impact have been?
I happen to have district-level presidential votes for each of these elections (but not, yet, for 2012*). The graph below plots both the actual and hypothetical** electoral vote percentages for each party against the popular vote. Red for Republican, blue for Democrat. The solid symbols indicate the actual percentage of electoral votes obtained, while the open symbols indicate the hypothetical allocation by congressional district. The plotted curves are local regression (lowess) curves for each party under each condition (solid for actual, dashed for hypothetical).
The exercise shows how any discussion of shifting to this method of allocation should be talked about for what it is: a GOP-biased proposal. Note that, under the actual allocation, the two curves are close to one another, at least through the part of the graph where it really matters–the relatively close elections. There does appear to be a slight Republican bias in the actual method, as that party’s line crosses over 50% of the electoral votes at almost exactly 50% of the (two-party) popular vote, while the curve for Democrats crosses over at just over 50% of the popular vote. In other words, the data plot predicts the Democrat needs a bigger vote lead to get the electoral vote majority. But the effect appears very small, consistent with what Thomas, King, Gelman, and Katz find.
However, under the hypothetical congressional-district allocation, there is a clear Republican bias. The Republican curve crosses over 50% of the electoral vote well to the left of the 50% popular-vote line, while that for Democrats does not break over 50% of the electoral vote until the party has a clear majority of the popular (two-party) vote.
The 2012 result is shown in the graph for the actual allocation, though I did not have the district data readily available. The 2012 result closely matches the fitted curve for the actual result. If it also matched the fitted curve for district allocation, the electoral-college result would have been very close indeed.***
Only in the case of landslides in the popular vote does the congressional-district method result in greater “proportionality”, as indicated by the flatter curve for congressional-district allocation. Otherwise, there is no sense in which the Republican proposal is “proportional“; rather, it is a partisan power grab. It is a power grab especially when employed only in states where the Republican candidate tends to have a better geographical spread of the votes in the state; it is a power grab even if employed for all electors, as assumed in the hypothetical allocations shown here.
Let’s turn to individual elections. Below is the change for the Republican candidate in electoral votes if the congressional-district method had been used instead of the actual statewide winner-take-all:
As we already saw from the graph, in landslide years, the Republican wins fewer electors via congressional districts. The only electoral-college landslides we have had during this time have been by the Republican candidate: 1972, 1980, 1984, 1988. All of these but 1980 were also huge wins in the popular vote. In every election since 1992, the Republican gains electors regardless of whether he wins or loses the actual election. He also gains in 1976. (In 1968, both major-party candidates lose electoral votes, as George Wallace obtains 56 under the congressional-district allocation, against the 46 he actually won.)
In 2004, despite its being a very close election, Bush would have won 317 electoral votes with a district plan, against the actual 286. His total also would have been better in 2000: 286 vs. the “actual” 271. Had Florida’s electors been awarded properly in 2000 under statewide allocation, Bush’s total would have been only 246, meaning that the congressional-district plan would have netted him 40 extra electors, despite losing the popular vote. That’s even more than his 31-elector gain in 2004, when he actually won the popular vote. (It might have been a slightly bigger change in 2000, as I am missing three districts that year: AR3, IN10 and LA2. For two of these, congressional votes are also missing; IN10, is a very safe Dem district in 2000 House race.)
Of course, an objection to any simulation such as this is that we do not know how campaign strategy might have changed under different rules. That is certainly true; if each House district actually would have awarded an electoral vote, campaigns would have targeted the marginal districts, some of which would have swung the other way. In other words, the votes themselves could have been different.
We can get a broad understanding of the opportunities for potentially swinging electoral votes by considering how often a district is marginal in the presidential contest.
There are 4,782 observations.**** There have been 730 the entire time that were decided by less than 5 percentage points (15.26%).
Of course, this varies a great deal by year, as shown below (number in parentheses indicates winner’s margin under a congressional-district allocation):
1968, 71 (104)
1972, 28 (410)
1976, 102 (2)
1980, 77 (247)
1984, 36 (398)
1988, 61 (216)
1992, 103 (106)
1996, 82 (152)
2000, 62 (37)
2004, 44 (96)
2008, 64 (64)
Obviously, 1976 could have been swung by district-focused campaigning: there were many more close districts than the margin (two electors!) that Carter would have won by under a district-based allocation. Not surprisingly, 2000 is another year when districts within the margin of 5% outnumbered the overall electoral-vote margin under the hypothetical allocation. In 2008 there are as many close districts as the electoral-vote margin, and in 1992 the two figures are within a few districts of one another. Looking only at these four elections, we can see which party had the greater number of marginal district wins.
year Rep Dem
1976 62 40
1992 46 57
2000 27 35
2008 37 27
This suggests that Bush’s district-based win in 2000 would have been relatively secure, as he had fewer close races to defend against the Gore campaign’s (hypothetical) district-swing efforts. And there would have been little risk of the Republican swinging the 1992 or 2008 outcome, though the Republican could have made the race closer. But 1976 really would have been a complete toss-up, depending on how various individual district contests turned out.
We might think that the candidate who trails in the popular vote would have more marginal districts to defend, but this is not true in either 1992 or 2000.
All in all, it is clear that congressional-district allocation of electors benefits one party more than the other, and that in a close election, the Republican candidate would be likely to have an advantage. The Republican might even be able to win with less than 49% of the two-party vote.
It is easy to see why Republicans might like a district-based electoral college. It is much harder to see why anyone would think it was a democratic (small or large d) improvement over the current method, bad though that may be.
I am actually somewhat happy that some Republicans have opened the issue of electoral-vote allocation. The country needs this conversation. However, what it needs is not one party pushing a plan that would be blatantly distorting in its favor. It needs the Democrats to engage the conversation, and come out in favor of the National Popular Vote plan, which would remove partisan bias from presidential elections.
* See sixth comment, below.
** As is standard for such proposals, I assume that the winner of the statewide plurality of the popular vote would be awarded two electors, in addition to a number corresponding to the number of individual House districts won. Two small states, Maine and Nebraska, are the only two states to have used such an allocation in at least some of the years analyzed.
*** Andrew Gelman suggests that Romney might have won, given the “huge” distortion of congressional-district allocation.
**** Would be 435*11=4,785, if not for the missing districts.