The season of Republican recrimination has dawned. The favorite rationalization for the candidate’s drift toward double digit deficits in the polls seems to be that the smears against Obama came too late and looked too desperate. If only McCain had descended into the mire months ago—things might have been different. There is no evidence, of course, that the old Rovian road, no matter when taken, would have led back to the White House in 2008. In serious times, assaults on Ayers and ACORN seem frivolous; and appeals to fear and intolerance don’t win votes, they merely stoke hate and incite right-wing believers.

New York Times columnist William Kristol, who once recommended war on Obama’s character, now urges McCain to “fire the campaign” that followed Kristol’s advice. But mixed messages are the essence of McCain’s exertions. The candidate suffers grievously from a dual sense—first that he has no credible plan to deal with the economic issues he’s said he doesn’t understand and, second, that he’s not steady, but erratic, irascible, lurching from position to position as he wanders around the stage.

Unmoored from strategic coherence, the candidate and his advisors jump from tactic to tactic searching compulsively for the latest trick. This is the driving force behind the campaign’s biggest mistake: selecting the unvetted, unserious Sarah Palin as a running mate. The hasty turn to Palin was based on a series of off-the-cuff assumptions—that she could attract Hillary voters, appeal to women generally, and substitute for the unacceptably pro-choice Joe Lieberman as a way to restore McCain’s brand as a maverick. The aim of this Hail Mary pass was somehow to switch the playing field from the economy to earmarks.

The calculation was wrong on every count. After an initial bounce generated by the bouncy Palin, most Hillary supporters recoiled from a caricature of the woman president or vice president they someday hope to see. Palin’s obvious lack of competence has pushed a rising tide of moderate women and independents toward Obama. Palin can’t even get through a Sunday talk show or a non-Fox network interview. She can do a fraction of the job of a running mate—read a speech—but the rest is beyond her.

Palin hasn’t broadened McCain’s appeal; she has narrowed it to a shrunken Republican base that is seething with resentment, often openly bigoted and clearly insufficient to win the election. The vituperation that marks rally after rally on the Republican side is alienating voters. Palin, who is now far more barracuda than hockey mom, has become the symbol of it.

Back in the Gore campaign of 2000, my former partner Tad Devine expressed his doubts about Lieberman as a running mate by telling Gore: “Mr. Vice President, you need Mr. October, not Mr. August.” Sarah Palin glaringly fails that test; she provided instant gratification, but then the bubble deflated. One reason the McCain campaign became so distracted in September was its constant scramble, from Troopergate to the Biden debate, to keep up the pretense that Palin is minimally plausible. And what kind of “reformer” picks a running mate under active investigation for abusing the power of her office?

Now when Americans think of McCain’s vice presidential choice, they see him as someone willing to do anything, say anything, to get elected. The impression overhangs his entire campaign. Maybe that’s why, in his latest game plan, Palin has been assigned to a back seat on McCain’s express to nowhere.

Even some mainstream Republicans have concluded that Palin is proof that party loyalty can ask too much. Frum rated the Palin pick as "bold" and "shrewd"—and perhaps irresponsible. He was right on one count.

She won’t know what this means since she religiously avoids Harry Potter, but Palin has shape-shifted from being an engaging curiosity to being a hit-woman, from moose hunter to media quarry. Today, she has the worst ratings of any candidate on either ticket. She’s a mistake so vast that she contains all the hollowness of McCain’s nasty campaign.

As he lurches toward November, McCain’s Palin experience is the political equivalent of a lost college weekend—that wacky, self-indulgent party where you tied one on and spent the night with the wrong date. It’s fun for a moment. But then comes morning and a hangover and—oh no—the wrong person is still there.