There's no way to be sure, but she might have won by even more than Obama did.

Voters in the Obama-McCain race said they would have preferred Hillary Rodham Clinton over McCain by 51 percent to 41 percent, a larger margin than Obama's 53-46 win.

Among the differences: Women say they would have backed Clinton over McCain by 18 percentage points, bigger than Obama's 12-point advantage with them. Whites favored McCain over Obama by 12 points but leaned toward the Republican by a narrower 5 points against Clinton. Eighty-six percent of blacks would have backed Clinton — solid, but shy of the 95 percent who supported Obama. Clinton almost matched the two-thirds of people under age 30 who voted for Obama, but nearly one in 10 of them said they wouldn't have bothered voting at all.