So, in other words, Kerry is sunk. Radley has a particularly telling way of pointing out the differences:
Think back to 2000. Gore mopped the floor with Bush on policy. He had a far better grasp of the issues, was far more articulate, and presented a far clearer vision (I thought that back in 2000 -- and I voted for Bush). Problem was, Gore was an asshole. As one analysis I read put it, Bush came off as the affable kid who never came to class prepared, but was likeable, and cut jokes at the back of the room. Gore came off as the kid who reminded the teacher that she forgot to collect the homework.
Voters still open to being swayed by the debates aren't as interested in policy as they are in personality. It's all about the "guy you'd rather have a beer with." That pans out once you go back over the last few elections: Bush over Gore. Clinton over Dole and Bush Sr. Reagan over Mondale and Carter.
And let's face it. Kerry's a schmuck. Or at least he comes off as one. If Gore was the kid who reminded the teacher to collect the homework, Kerry's the prep school trust-funder who drives a Beamer and ties a pastel Izod across his shoulders. If swing state demographics resembled Greenwich, Connecticut, he'd be golden.