Sarah Palin makes John McCain look even older than he is. And he seemed more than willing to play that part on Thursday night. By the time he slogged through his nearly 50-minute acceptance speech - longer even than Barack Obama's - you half-expected some brazen younger Republican (Mitt Romney, perhaps?) to dash onstage to give him a gold watch and the bum's rush.

    Still, attention must be paid. McCain's address, though largely a repetitive slew of stump-speech lines and worn G.O.P. orthodoxy, reminded us of what we once liked about the guy: his aspirations to bipartisanship, his heroic service in Vietnam, his twinkle. He took his (often inaccurate) swipes at Obama, but, in winning contrast to Palin and Rudy Giuliani, he wasn't smug or nasty.

    The only problem, of course, is that the entire thing was a sham.

    As is nakedly evident, the speech's central argument, that the 72-year-old McCain will magically morph into a powerful change agent as president, is a non sequitur. In his 26 years in Washington, most of it with a Republican in the White House and roughly half of it with Republicans in charge of Congress, he was better at lecturing his party about reform than leading a reform movement. G.O.P. corruption and governmental dysfunction only grew. So did his cynical flip-flops on the most destructive policies of the president who remained nameless Thursday night. (In the G.O.P., Bush love is now the second most popular love that dare not speak its name.)

    Even more fraudulent, if that's possible, is the contrast between McCain's platonic presentation of his personal code of honor and the man he has become. He always puts his country first, he told us: 'I've been called a maverick.' If there was any doubt that that McCain has fled, confirmation arrived with his last-minute embrace of Sarah Palin.

    We still don't know a lot about Palin except that she's better at delivering a speech than McCain and that she defends her own pregnant daughter's right to privacy even as she would have the government intrude to police the reproductive choices of all other women. Most of the rest of the biography supplied by her and the McCain camp is fiction.

    She didn't say 'no thanks' to the 'Bridge to Nowhere' until after Congress had already abandoned it but given Alaska a blank check for $223 million in taxpayers' money anyway. Far from rejecting federal pork, she hired lobbyists to secure her town a disproportionate share of earmarks ($1,000 per resident in 2002, 20 times the per capita average in other states). Though McCain claimed 'she has had national security as one of her primary responsibilities,' she has never issued a single command as head of the Alaska National Guard. As for her 'executive experience' as mayor, she told her hometown paper in Wasilla, Alaska, in 1996, the year of her election: 'It's not rocket science. It's $6 million and 53 employees.' Her much-advertised crusade against officials abusing their office is now compromised by a bipartisan ethics investigation into charges that she did the same.

    How long before we learn she never shot a moose?

    Given the actuarial odds that could make Palin our 45th president, it would be helpful to know who this mystery woman actually is. Meanwhile, two eternal axioms of our politics remain in place. Americans vote for the top of the ticket, not the bottom. And in judging the top of the ticket, voters look first at the candidates' maiden executive decision, their selection of running mates. Whatever we do and don't know about Palin's character at this point, there is no ambiguity in what her ascent tells us about McCain's character and potential presidency.

    He wanted to choose the pro-abortion-rights Joe Lieberman as his vice president. If he were still a true maverick, he would have done so. But instead he chose partisanship and politics over country. 'God only made one John McCain, and he is his own man,' said the shafted Lieberman in his own tedious convention speech last week. What a pathetic dupe. McCain is now the man of James Dobson and Tony Perkins. The 'no surrender' warrior surrendered to the agents of intolerance not just by dumping his pal for Palin but by moving so far to the right on abortion that even Cindy McCain seemed unaware of his radical shift when being interviewed by Katie Couric last week.

    That ideological sellout, unfortunately, was not the worst leadership trait the last-minute vice presidential pick revealed about McCain. His speed-dating of Palin reaffirmed a more dangerous personality tic that has dogged his entire career. His decision-making process is impetuous and, in its Bush-like preference for gut instinct over facts, potentially reckless.

    As The New York Times reported last Tuesday, Palin was sloppily vetted, at best. McCain operatives and some of their press surrogates responded to this revelation by trying to discredit The Times article. After all, The Washington Post had cited McCain aides (including his campaign manager, Rick Davis) last weekend to assure us that Palin had a 'full vetting process.' She had been subjected to 'an F.B.I. background check,' we were told, and 'the McCain camp had reviewed everything it could find on her.'

    The Times had it right. The McCain campaign's claims of a 'full vetting process' for Palin were as much a lie as the biographical details they've invented for her. There was no F.B.I. background check. The Times found no evidence that a McCain representative spoke to anyone in the State Legislature or business community. Nor did anyone talk to the fired state public safety commissioner at the center of the Palin ethics investigation. No McCain researcher even bothered to consult the relevant back issues of the Wasilla paper. Apparently when McCain said in June that his vice presidential vetting process was basically 'a Google,' he wasn't joking.

    This is a roll of the dice beyond even Bill Clinton's imagination. 'Often my haste is a mistake,' McCain conceded in his 2002 memoir, 'but I live with the consequences without complaint.' Well, maybe it's fine if he wants to live with the consequences, but what about his country? Should the unexamined Palin prove unfit to serve at the pinnacle of American power, it will be too late for the rest of us to complain.

    We've already seen where such visceral decision-making by McCain can lead. In October 2001, he speculated that Saddam Hussein might have been behind the anthrax attacks in America. That same month he out-Cheneyed Cheney in his repeated public insistence that Iraq had a role in 9/11 - even after both American and foreign intelligence services found that unlikely. He was similarly rash in his reading of the supposed evidence of Saddam's W.M.D. and in his estimate of the number of troops needed to occupy Iraq. (McCain told MSNBC in late 2001 that we could do with fewer than 100,000.) It wasn't until months after 'Mission Accomplished' that he called for more American forces to be tossed into the bloodbath. The whole fiasco might have been prevented had he listened to those like Gen. Eric Shinseki who faulted the Rumsfeld war plan from the start.

    In other words, McCain's hasty vetting of Palin was all too reminiscent of his grave dereliction of due diligence on the war. He has been no less hasty in implying that we might somehow ride to the military rescue of Georgia ('Today, we are all Georgians') or in reaffirming as late as December 2007 that the crumbling anti-democratic regime of Pervez Musharraf deserved 'the benefit of the doubt' even as it was enabling the resurgence of the Taliban and Al Qaeda. McCain's blanket endorsement of Bush administration policy in Pakistan could have consequences for years to come.

    'This election is not about issues' so much as the candidates' images, said the McCain campaign manager, Davis, in one of the season's most notable pronouncements. Going into the Republican convention, we thought we knew what he meant: the McCain strategy is about tearing down Obama. But last week made clear that the McCain campaign will be equally ruthless about deflecting attention from its own candidate's deterioration.

    What was most striking about McCain's acceptance speech is that it had almost nothing in common with the strident right-wing convention that preceded it. We were pointedly given a rerun of McCain 2000 - cobbled together from scraps of the old Straight Talk repertory. The ensuing tedium was in all likelihood intentional. It's in the campaign's interest that we nod off and assume McCain is unchanged in 2008.

    That's why the Palin choice was brilliant politics - not because it rallied the G.O.P.'s shrinking religious-right base. America loves nothing more than a new celebrity face, and the talking heads marched in lock step last week to proclaim her a star. Palin is a high-energy distraction from the top of the ticket, even if the provenance of her stardom is in itself a reflection of exactly what's frightening about the top of the ticket.

    By hurling charges of sexism and elitism at any easily cowed journalist who raises a question about Palin, McCain operatives are hoping to ensure that whatever happened in Alaska with Sarah Palin stays in Alaska. Given how little vetting McCain himself has received this year - and that only 58 days remain until Nov. 4 - they just might pull it off.