As the presidential campaigns shift their focus to the general election, there’s a big question about where the battleground will be. Which states will be competitive? What state will be the tipping point? The unusual candidacy of Donald Trump has some people wondering whether the electoral map will look different this year than it has in the past.
There are good reasons to think the map won’t change much; John Sides and Andrew Gelman, for example, recently suggested that, because states are moving increasingly in unison from election to election, it is unlikely that Trump can “scramble” the map.
But new data that I have analyzed with Bernard Fraga of Indiana University tells a different story.
The premise of this story is that although recent presidential elections have featured a predictable set of swing states and safe states, the extraordinary unpopularity of both major candidates (especially Trump) might mean that voter enthusiasm — and therefore turnout — might be different from that of past years. Additionally, Trump is so unlike recent Republican nominees that the past few presidential election results might not be very predictive of his performance.
Suppose, therefore, that we broaden our view and investigate where Democrats and Republicans have generated close contests beyond presidential races. Surprisingly, nearly the whole country has seen very close contests during the past few years.
Consider this map...