“He loves being the underdog, and for a certain period of time he looked like the underdog against J. D. Hayworth,” says Torie Clarke, McCain’s former press secretary, who first went to work for him in the mid-1980s. “On a day-to-day basis, I’ll bet he enjoys it. On a long-term basis, looking back on the last 40 years of his life, I don’t know.” She adds, “I think a fair number of people who’ve worked with him over the years look at him—and what he has to do to win this campaign—and say, ‘Is it really worth it?’ He seems to be sacrificing some of the principles he holds dear. He seems to be making compromises he wouldn’t have made 10 or 15 years ago.”

Only in a brief news conference with the handful of reporters who showed up to cover the debate did McCain give a small, sad, unintended insight into what he—who commanded the attention of the whole country and won the votes of nearly half the electorate just 24 months ago—must be thinking these days. He said he is confident that when they examine his record “the American …the people of Arizona” will make the right choice.

THE ANGER OF THE TEA PARTY WING HAS MADE MANY REPUBLICANS TWIST THEMSELVES INTO CARICATURES. FOR McCAIN, THE GAMBIT WORKED.

The prevailing question about John McCain this year is: What happened? What happened to that other John McCain, the refreshingly unpredictable figure who stood apart from his colleagues and seemed to promise something better than politics as usual? The question may miss the point. It’s quite possible that nothing at all has changed about John McCain, a ruthless and self-centered survivor who endured five and a half years in captivity in North Vietnam, and who once told Torie Clarke that his favorite animal was the rat, because it is cunning and eats well. It’s possible to see McCain’s entire career as the story of a man who has lived in the moment, who has never stood for any overriding philosophy in any consistent way, and who has been willing to do all that it takes to get whatever it is he wants. He himself said, in the thick of his battle with Hayworth, “I’ve always done whatever’s necessary to win.” Maybe the rest of us just misunderstood.

McCain has always lived for the fight, and he has defined himself most clearly in opposition to an enemy, whether that enemy was the rule-bound leadership of the United States Naval Academy, his North Vietnamese captors, the hometown Arizona press corps that never much liked him, his Republican congressional colleagues, the Reverend Jerry Falwell, George W. Bush, Donald Rumsfeld, Barack Obama, or J. D. Hayworth. He has always been more of an existential politician than a consequential one, in the sense that his influence has derived not from steady, unswerving pursuit of philosophical goals or legislative achievements but from the series of unpredictable—and sometimes spectacular—fights he has chosen to pick. As his daughter Meghan recently wrote, he has always been more of a craps guy than a strategic poker player. He has never been a party leader, like his old friend Bob Dole, of Kansas, or a wise elder, like his colleague Dick Lugar, of Indiana, or a Republican moderate, like Susan Collins and Olympia Snowe, of Maine. He flies solo, first, last, and always, and his paramount cause has always been his own. That is the bracing reality of John McCain. It is the tragedy, too.

There is no doubt that being John McCain 2010 is a colossal comedown for a man who was described just three years ago by The Almanac of American Politics as “the closest thing our politics has to a national hero.” Beginning with his 2000 presidential campaign, which climaxed in his stunning 18-point upset victory over George W. Bush in the New Hampshire primary and cratered just weeks later in bitter defeat in South Carolina, McCain redefined the image of the Happy Warrior in politics for a generation of Americans long unaccustomed to the sight, conducting a freewheeling, subversive seminar on his campaign bus, the Straight Talk Express. He seemed, somehow, above conventional politics, if only because he wasn’t above letting the world know that he thought the game, as it had come to be practiced, was a joke. In defeat, he voted against George W. Bush’s initial tax cuts (because, he said at the time, such cuts would go disproportionately to the rich, and later because he feared there would be no compensating cuts in spending), and he was unsparing in his criticism of the administration’s conduct of the wars in Iraq and Afghanistan and of its embrace of torture in interrogations of suspected terrorists. Had he shown the slightest interest in his friend John Kerry’s importunings, he might well have been the Democratic vice-presidential nominee in 2004. He went to work with Democrats such as the late Ted Kennedy to bring sanity, and humanity, to the nation’s long-running debate over illegal immigration. And at a time when such a position entailed nothing but political dangers, in his own party and with the electorate at large, he was steadfast in maintaining that the country should commit more troops to Iraq, not withdraw the forces already there.