Based on virtually all the polls since late September, the odds are obviously in Obama's favor, but Mark Blumenthal of pollster.com flags one variable that may favor McCain:
"But there is one remaining theoretical possibility that amounts to the 'nightmare scenario' for pollsters. What if those who refused to be interviewed have very different political views than those who agreed to participate?
"This concern is far from trivial, as even the most rigorous national surveys struggle to achieve response rates over 30 percent. And it is hard to know much for certain about those who do not respond because, obviously, we cannot interview them."
"While they always weight this group up to its appropriate level, he could not rule out the possibility that the missing respondents may be those with less racial tolerance, as they were in Pew's 1997 study."
Via the Atlantic's cool-headed, analytical Marc Ambinder.