Some polls show Obama with a healthy lead even without an assumed surge in African American and young voters. Obama's seven-point lead in the Washington Post-ABC News poll is not premised on disproportionately higher turnout among those demographic groups. The poll's turnout model currently shows that 10 percent of likely voters are black, compared with the 11 percent who voted in 2004, according to the network exit poll. Voters younger than 30 make up 16 percent of the Post-ABC sample, little different from the 17 percent four years ago.

Post polling director Jon Cohen said the survey designers "carefully consider a range of likely voter scenarios and use our best judgment. Our polling throughout the campaign has been on target and, we believe, helpful to understanding what is really happening. I hope it stays that way."

I've said it before - the WaPo pollster Gary Langer has proven to me he is the best in the business. From 2004, when ABC nailed the presidential election (I railed against the poll at the time because I thought it had too many undecideds breaking to Bush, they were right and we who complained were wrong), to the 2006 congressional elections to this years presidential primaries, they have been, as the WaPo pollster Jon Cohen says, on target.

I think they are wrong on the turnout but I must admit they have a great track record.

By Big Tent Democrat, speaking for me only