SALEM, New Hampshire—Chris Christie was accustomed to being a big man: a man of stature, a man of power, a man who demands and gets his way.

But recently, the big man (this is a description of his personality, not his size) was seeming awfully small.

On Friday evening here, the governor of New Jersey was desperately trying to talk some sense into the people of New Hampshire, a couple hundred of whom had come out to see him on a snowy night. The night before, Christie’s rival Marco Rubio had played the same venue, filling a larger room of the elementary school beyond its capacity. Christie was begging the crowd not to pile on the bandwagon of the apparent winner, but instead, to show some courage.

“I can’t tell you how many people have called me and said”—he stage-whispered into the handheld cordless microphone—“‘I think you’re the best, I really do. After you win a few things, and it looks like for sure you’re going to be the nominee, I’ll be happy to be with you.’ I’m like, I don’t need you then!

A losing presidential campaign can humble even the biggest politician’s ego, and for Christie, the journey has been long and humbling indeed. Now, after a powerful performance in Saturday’s debate, Christie hopes for a turnaround—but even if he falls short, the once-mighty pol may have achieved some satisfaction by reestablishing his dominance, if only for an instant.

Slugging it out on the campaign trail last week, Christie seemed decidedly subdued. The flashes of pugilistic verve at his famous town-hall meetings were fewer, and came farther between. The crowds were modest, the contingent of reporters small. He struck a tone of centrist competence, emphasizing the effective functioning of government rather than partisan red meat. In Stratham, on Friday afternoon, he even managed to have a friendly conversation with Rachel Maddow, the MSNBC host who had long been his nemesis.

But sometimes Christie could not help himself—he reminded the crowd, subtly, how high his stock once rose. How, in the summer of 2011, some of the tri-state area’s biggest GOP moneymen were so down on Mitt Romney and the rest of the 2012 contenders that 60 of them, led by the Home Depot co-founder Ken Langone, gathered at a club in Manhattan and beseeched him, saying, “Your country needs you,” and promised to give him all the money he needed.

How the drumbeat from the press got so intense that Christie mock-threatened to kill himself: “Short of suicide, I don’t really know what I’d have to do to convince you people that I’m not running!” And they laughed, and reported it as another great Christie-being-Christie anecdote—and kept right on asking.

But Christie still said no, and now, he would like some credit for that.

“I didn’t run four years ago because I wasn’t ready for that responsibility,” he told the audience in Salem. “I'd been governor for 18 months. And I saw the political opportunity, believe me.” You couldn’t help but notice the rueful edge in his voice. “And there were a lot of people who wanted me to run. But I made the decision—I'm not going to run for president—because in my heart, I wasn't ready.” He didn’t want, he said, to be like a certain other newly elected pol who took the opportunity when it was offered, then got to the Oval Office and didn’t know what the heck to do.

“I’m ready now,” he said. “I’ve been tested.” By the rough-and-tumble politics of New Jersey, by a momentous natural disaster, by the vicious New York media. “I waited until I was ready,” he added, “and I’m ready now.”

Hadn’t he still got it? Christie seemed to be asking, between the lines. Wasn’t he the same man who once brought the unions to heel, who gallantly dug out his state from a catastrophic storm (standing by the president’s side, because it was bigger than politics), who seemed so potent and unstoppable? Who gave the keynote speech at the 2012 Republican convention? Who got reelected in November 2013 with a staggering 60 percent of the vote in his blue state, launching a thousand cable-news segments about his formidable national prospects? The Associated Press article on his reelection began this way: “Gov. Chris Christie was re-elected with ease Tuesday, demonstrating the kind of broad, bipartisan appeal that will serve as his opening argument should he seek the Republican presidential nomination in 2016.”

It was just a few weeks later that the trouble began—the revelations about the strong-arm tactics his aides had used to build that broad bipartisan appeal, threatening a Democratic mayor with “traffic problems” if he didn’t lend his endorsement. Bridgegate, as it came to be called, was a huge deal because Christie was a big deal. It consumed the national media for days. When, in January, he finally gave a long press conference to apologize and explain, the cable networks carried it live and breathlessly dissected it. Was Christie finished? they wanted to know. It seemed unthinkable.

These days, hardly anyone ever brings up the bridge. Is that because people have moved on? Or because he’s just not important enough to scare anyone anymore?

Down but not out, Christie ran for president anyway, even though this time no one was begging him to. The moneymen were mostly gone; Langone said he’d write a check, but not a big one.

Christie labored in the single digits in the polls. He talked about terrorism and entitlement reform. At one point, he didn’t make the main debate stage, appearing in the junior-varsity pre-prime-time stakes instead.

He camped out in New Hampshire, where he has labored for months to bring the magic back, inch by painful inch. He has made them laugh and made them cry. He has earned the endorsement of more local officials than anyone, plus the state’s biggest newspaper, the crusading, partisan Union Leader. He has answered their questions, over and over, in rollicking, sometimes combative town-hall meetings that can go for hours.

Around the beginning of the year, it seemed to be paying off. The polls, those elusive, meaningless barometers of the voters’ fickle moods, showed him moving slightly upward in New Hampshire. So naturally Newton’s third law kicked in, in the form of the super PAC backing Marco Rubio, which began airing advertisements showing Christie hugging Obama and ticking off his liberal positions.

Christie’s numbers zoomed back down. Rubio, meanwhile—the slender, athletic golden boy, he of the effortless charisma and spotty voting record—came in third in Iowa and was immediately hailed by the commentariat as the man who would single-handedly save the Republican Party from its chaos and torpor.

This was apparently too much for Christie. It was time for the big man to take matters into his own hands.

Over the past week, Christie attacked Rubio in starkly personal terms, calling him a sheltered lightweight and worse. “Maybe he’ll do more than 40 minutes on a little stage telling everybody his canned speech that he’s memorized,” Christie said in Bedford on Tuesday, voice dripping with disdain. “This isn’t a student-council election, everybody. This is an election for president of the United States. Let’s get the boy in the bubble out of the bubble.” He added, “It’s time for him to man up and step up and stop letting all of his handlers write his speeches and handle him.”

At every town hall, a version of this pitch was near the top of Christie’s remarks (which, it should be said, are loose and fluent, but certainly include their share of talking points and practiced, word-for-word spiels): a warning not to elect a callow, first-term U.S. senator with no accomplishments to speak of. Rubio, he told the audience in Salem—a bright floodlight behind him, a blue banner reading “CHRISTIE 2016: TELLING IT LIKE IT IS”—“gives the same six answers to every question. Right now, because they like him, they call him disciplined.” There was, he implied, another word for it.

And so it should have come as no surprise to Rubio when, on Saturday, Christie roared into the final debate before the New Hampshire primary and locked onto his target. The moderators tossed Christie a strike right over the plate. He leveled exactly the criticism of Rubio he’d been making for days—and Rubio froze.

“There it is!” Christie cried, after Rubio repeated the same odd line for the third time in a row. “There it is. The memorized 25-second speech. There it is, everybody.” The old prosecutor was up there, cross-examining the witness, and all the witness could do was cling to his ever-more-implausible story. By the time the debate was over, Christie's pummeling of Rubio was the big headline of the night.

The next day, Sunday, Christie took a victory lap. “I think the whole race changed last night,” he said on CNN. “What I've been saying about Senator Rubio was on full display last night,” he said on Fox. “When the lights go on, I told you he wouldn’t be ready,” he told a town-hall audience in Hampton. Christie’s staff added an extra event to his schedule so he could gloat some more.

In the early evening, he glided into Cactus Jack’s in Manchester, which was packed with a pre-Super Bowl rush of people wearing Christie stickers. A cheer went up as he worked his way through the crowd, the mingled smells of steak fries and tacos wafting through the air. “We had a good time last night in that debate, what’d you think?” he grinned, as a clutch of cameras captured the moment.

He was still a long shot, with a lot of ground to make up between Christie and the prize he sought. But for one shining day, Chris Christie was back in the spotlight, where the big man believed he rightly belonged.