The Democratic euphoria, and Republican gloom, that spread in the wake of President Obama’s convention bounce abated a bit after ABC News and the Washington Post released a new poll showing Obama leading Romney by just a point among likely voters. Given that Obama’s convention bounce is certain to fade, this seems like really good news for Romney. It sort of is, but not in the way it seems.
The thing I’ve been harping on for months is racial composition. Obama has held very steady support among non-white voters, so the key factor is his share of the white vote. Where polls have tended to differ is how many white people will turn up at the polls. The ABC/Post poll shows Obama leading by six points among registered voters — a nice bounce, in line with what other polls show — but only a single point among likely voters. Why is that? Because the Post’s likely voter screen produces an electorate that’s about (according to political scientist Alan Abramowitz, via email) 80 perecent white — even whiter than the 2010 off-year elections, and off-year elections are always whiter than presidential elections. The fact that the Post’s likely voter screen is screening out massive numbers of non-white voters suggests that Obama may have work to do to turn them out, but it isn’t showing us a very plausible portrait of the electorate.
Both campaigns seem to be assuming an electorate that is about as diverse as the one four years ago — non-white voters will probably be a little less jazzed to vote, but more of them will be eligible. That assumption, combined with Obama’s steady share of the non-white vote, produces a break-even point of around 60 percent of the white vote, or perhaps a little higher, for Romney. In the Post’s likely voter sample, he only leads by 55 to 42 percent among white voters. That thirteen-point lead is nowhere close to the twenty-point-plus margin he probably needs.
The upside in the poll for Romney is that registered voters still give Obama just a 48 percent approval rating, against 50 percent disapproval. That is a fairly dangerous sign for Obama.
It’s dangerous because the immediate wake of the Democratic convention is probably the high point of the race for him. Obama can pull in voters who don’t approve of him — they just like Romney even less — but he can’t pull in that many of them. He needs to stay close to 50 percent, he’s likely to drop when the convention bounce wears off, and he can’t drop very far. Likewise, none of the polls showing him opening up a sizable lead have Obama climbing much above 50 percent (the Post has him at exactly 50 percent among registered voters, which also happens to Obama's standing in today's Gallup tracking poll of registered voters.)
The conventions have tested the candidate’s ceilings — they show the candidate in the best light and then see who might support them then. Obama’s ceiling appears higher than Romney’s. But it’s not very high. There’s not going to be an Obama landslide. His path looks a lot like George W. Bush’s in 2004 — that is, 51 percent of the vote. That happens to be right about where he stands in Nate Silver’s forecast.