Photo: Matt Sullivan/2012 Getty Images

Who’s winning the presidential race? There’s an odd disconnect between the polls and the body language of the candidates. John Harris and Alexander Burns report from Tampa, “Republicans believe Obama’s governing defects should make a GOP victory virtually inevitable, but Romney’s political defects make it only a long-shot possibility.” Likewise, Mark Halperin, after extensive discussion with Obama’s campaign team, remains convinced that the campaign is not bluffing about its belief that it remains ahead in the race and unlikely to lose barring an unforeseen external event.

Could they be spinning? Possibly, though the more self-interested spin for Obama would probably emphasize the closeness of the race (send money! volunteer!) rather than the unlikelihood of defeat. In any case, the actual behavior of both campaigns suggests agreement on this point. Obama is running the same game plan he embarked on last year. Romney has changed things up, junking his original game plan — portraying Obama as a good guy over his head and hoping to make the election a referendum on the economy — to instead emphasize hard-edged attacks on the president and use Paul Ryan to shake up the race. So, however much Romney blusters, his deeds suggest a decided lack of confidence.

The curious thing is that this take is not reflected in the national polls. A Washington Post poll of registered voters yesterday had Romney leading by a point; a CBS poll today shows Obama up by one. Note that registered voters traditionally skew their picture toward the Democrats by around a couple percentage points, since not all registered voters cast a ballot, and Republicans are usually more likely than Democrats to show up at the polls. That would suggest that Romney is actually up by a couple points.

So, what gives?

The best explanation I can muster is that the polls are assuming a much different, and more GOP-friendly, electorate than either party. ABC’s poll assumes that 78 percent of registered voters are white. That is … a whole lot of white people. The white share of the electorate has been dropping steadily for more than twenty years — from 87 percent in 1992 to 83 percent in 1996 to 81 percent in 2000, 77 percent in 2004, and 74 percent four years ago. Ron Brownstein’s recent reporting suggests that both campaigns expect an electorate that’s about 74 percent white. The same problem seems to appear in numerous other polls. Many of them don’t release their racial breakdowns, but those that do seem to imply electorates far whiter than the campaigns are banking on. As pollster Mark Blumenthal has exhaustively shown, Gallup has systematically underweighted the number of minorities in its polls, due to technical issues related to the difficulty of finding and weighting poll respondents.

Now, we don’t know what the racial composition of the electorate will look like. But it is utterly key. Assuming the 74 percent white makeup, and further assuming that Obama’s standing among nonwhite voters holds up as it has with high consistency, then Romney needs to win white voters by more than 20 points, perhaps by around 22 points, in order to prevail. Few polls show him doing that. The ABC poll has him winning whites by eighteen points.

Again, the racial composition of the electorate is a guess. It’s possible that nonwhite voters just won’t show up in the numbers either campaign seems to expect. But the best explanation I can come up with for the gap between the polls, on the one hand, and the apparent confidence of Obama’s camp (and the lack of confident in Romney’s revealed behavior) on the other, it’s that the polls are showing more white people than either campaign projects.