Then the picture darkened. McCain seemed to retreat into something reporters and staffers called “the bubble,” his traveling entourage. His inner circle of strategists turned out to be hard-bitten pols. Under fierce and sometimes underhanded attack, the candidate became more strident, even whiny, lashing out at his opponent for playing dirty. The press began to play the old “gotcha” game, catching McCain in “gaffes” that became three-day stories. On the last night, after McCain was blown out in the major primary states on Super Tuesday, the cameras caught him turning on NBC reporter Maria Shriver, who was demanding, “How do you feel?” “Please,” McCain growled. “Get out of here.”

How did the Straight Talk Express wind up in a ditch? In part, McCain was caught in a bind. It’s an axiom of modern politics that only losers let attacks go unanswered. “I’m not going to be like Bill Bradley,” McCain vowed early on. “If I get hit, I’m going to hit back twice as hard.” Yet to overcome Bush’s money and organization McCain needed to stay on the high road, stressing service and sacrifice for the nation. By responding to the mudslinging of Bush’s allies and attack ads, McCain began to look like just another self-absorbed politician. On Super Tuesday, polls showed that voters regarded McCain as no less negative than George W. Bush.

McCain’s biggest mistake may have been to take politics personally. With his outsize sense of honor, he was too ready to duel. On the bus, McCain’s staff–veterans of the rough-and-tumble of presidential campaigning–urged him to hit back. It is unusual for all the top campaign staff to travel with the candidate, but McCain’s campaign seemed so unique and exciting that his top staffers couldn’t bear to stay back at headquarters in Washington. McCain’s brooding chief strategist, John Weaver (sardonically nicknamed “Sunny” by McCain), and his campaign manager, Washington lobbyist Rick Davis, along with media guru Mike Murphy and speechwriter Mark Salter, formed the bubble around the candidate. The atmosphere of noble insurrection was intoxicating, perhaps too much so. “When I went back to Washington, I felt like I was behind enemy lines,” said Salter. McCain’s self-comparison to Luke Skywalker in “Star Wars” was playful hyperbole, but his campaign at times seemed to truly regard the Bush campaign as the Evil Empire. When McCain referred to the Christian right as the “forces of evil,” he had to spend the next three days arguing that he was really kidding.

McCain’s friends outside the bubble worried that he was succumbing to the wrong impulses, his own and his staff’s. With the freedom that comes from lack of direct responsibility, informal advisers like former Reagan chief of staff Ken Duberstein and Sen. Chuck Hagel of Nebraska began warning McCain to lighten up, to get back “on message” and forget about tit for tat with Bush. McCain’s anger at Bush, they argued, had knocked him off stride. “John, you’ve got to let it go. Flush it out, it’s consuming you,” Hagel says he told McCain. The candidate “understood it,” says Hagel, “but he couldn’t turn it around. One of the downsides of the boys on the bus is the echo chamber.”

On the bus in the final days, McCain was not so much angry as bewildered. “Can you believe this?” he wondered aloud, as Bush accused McCain of being soft on breast cancer. When he accosted Maria Shriver on election night, his tone was less bitter than weary. He seemed subdued and cool when he dropped out, and he is clearly in no rush to help Bush. Will McCain run again in 2004, when he will be 68? He has said no: that the first time was fun, but the second time would not be. If he does run, McCain has to at least recapture the freewheeling spirit of the Straight Talk Express–and keep his own willful pride in check.