Census Reapportionment Not Mattering in Obama/Romney Contest

In the last census, northeastern industrial states lost a bunch of electoral votes, and Sun Belt states gained a lot of electoral votes. Democrats tend to do better in the former than the latter. That's the kind of thing that can only matter in a close election, but we're in a close election, so the electoral math matters. Will this shift of electoral power from the left-leaning to the right-leaning parts of the country matter this time around? Well, I suppose we don't know what the actual map will look like just yet, but we can get a sense of how the states are lining up. If we make a "path of least resistance" map, i.e. assign states to each candidate in descending order of how likely (per 538's current forecast) they are to carry those states, we find that Ohio is the tipping-point state right now, i.e. for both the Obama and the Romney path-of-least-resistance winning map Ohio is the last state added to the tally. The map looks like this:

In this map, Obama has 253 electoral votes, Romney has 267, and Ohio's 18 are the tipping-point. If we give them to Romney, he wins 285-253, and if we give them to Obama, he wins 271-267. So the question is, would either scenario be changed by reverting to 2000 census figures?

Answer: no. Of the blue states on that map, Massachusetts, New Jersey, Pennsylvania, Michigan, and Illinois each lost a vote, while New York shed two electors and Nevada and Washington gained one apiece, for a net loss of 5 electors under the new figures. So Obama's 253 electoral votes in these states were 258 votes before the 2010 census; not enough for a victory. But, of course, if you tack on the 20 votes from Ohio, you've got 278, and an Obama win. So the path-of-least-resistance calculus would be identical with the 2000 numbers: if each candidate won every state that FiveThirtyEight currently considers them to be more likely to win than any state they do win (i.e., if each candidate takes a path of least resistance given the current 538 odds), it all comes down to Ohio.

We can monkey with this calculus a bit, however. Suppose Obama loses Ohio, but goes looking for backup options. His best bets are Iowa and New Hampshire, worth a combined 10 votes now and 11 votes last decade. Under the new lines, that gets him to 263, which is no good. Under the old lines, that would have been 269, good for a tie but then, almost certainly, a loss in the House of Representatives. Or what about Virginia? It's got 13 votes under both census counts, so adding Virginia to the blue states on that map gives 266 and a loss under the current lines, but 271 and a win under the old lines. Colorado's 9 votes under both censuses would get Obama to 262 or 267, neither of which is sufficient; however, under the old lines, Colorado plus New Hampshire would have done it.

Another wacky scenario would be if Obama were to win Florida, while losing some other states that look easier for him as of this instant. Tack Florida on to the map above and you get 282 electoral votes under the new lines, and 284 under the old lines--since Florida gained two votes, this reduces the difference. Obviously either would be enough for a win, but we can then peel off Obama's other marginal states: taking away Nevada gets us down to 276 new votes and 279 old votes, and then removing Wisconsin gets us 266 new votes, and a loss, and 269 old votes, and a loss-through-tie.

So in the scenario where Obama loses Ohio but makes up for it by winning either Colorado or Virginia, the 2010 census will have changed the result of the election, but in pretty much any other scenario, it won't have mattered.