That's a big lead, though including third-party candidates knocks it down to 12 points, as Nate Silver explains; his analysis is, as you might guess, sound. Here are some points that jumped out at me:
"Among independents who are likely voters - a group that has swung back and forth between McCain and Obama over the course of the campaign - the Democratic ticket now leads by 18 points. McCain led among independents last week.
"McCain's campaign strategy may be hurting hurt him: Twenty-one percent of voters say their opinion of the Republican has changed for the worse in the last few weeks."
"McCain's favorable rating has fallen four points from last week, to 36 percent, and is now lower than his 41 percent unfavorable rating. Obama, by contrast, is now viewed favorably by half of registered voters and unfavorably by just 32 percent.
"Obama holds a considerable edge over his rival on having the right 'personality and temperament' to be president, with 69 percent saying Obama does and 53 percent saying McCain does."
And here's the punchline:
"One in three voters say they have heard 'a lot' about Ayers, and 31 percent say they have heard something about him, though far fewer - 9 percent - say the association bothers them.
"Four percent of voters say that it bothers them that Obama is a Muslim, which he is not. Fifty-six percent say nothing about Obama’s past bothers them."
In other words, the difference between an active theme they've been pushing and a completely insane rumor is five points. Now, I take that to mean bringing up Ayers tomorrow night will only hurt McCain, and would surely be the takeaway moment instead of any new economic proposals. But now he's said he would. Oops.
McCain's even running behind Barack on the question of who would raise your taxes. In other words, he's finding new ways to fail. Stay tuned for my attempt to compete with Gwen Ifill, due after election day: Change: John McCain's Campaign Was Awful Plus a Sexier Thesis TK.
Update: Ian Welsh turns a skeptical eye on Obama's economic plan. His general thesis bears mentioning: don't be disappointed, what with all the enthusiasm and mixtapes and Walgreens T-shirts and whatnot, if Obama turns out to be a Clintonian neoliberal. I mean, be disappointed, I guess, but don't be surprised.