As the Republican presidential candidates round the final bend that old warhorse John McCain is coming up fast through the crowded field.

In Iowa, where voting starts in just eight days, the most recent poll, by American Research Group, puts him surging into second place, behind Mike Huckabee with support for Mitt Romney collapsing and Rudy Giuliani fast dwindling. In New Hampshire, the latest poll, by the Boston Globe, puts him in a statistical dead heat with Mr. Romney, with Messrs. Huckabee and Giuliani trailing far behind. In the latest national poll, by Fox News Messrs. McCain, Huckabee, and Giuliani are neck and neck and neck.

This is an unexpected triumph for the senator for Arizona, who until June had sat in second place behind Mr. Giuliani In the early summer that will o’ the wisp Fred Thompson overtook him, then in late November Mr. Huckabee came out of nowhere to pass him, and more recently Mr. Romney moved ahead of him on the national stage.

Senator McCain took his eclipse all in good part. Addressing a breakfast meeting of Hudson Institute members at the Four Seasons restaurant in New York a couple of months ago, he was noticeably sotto voce. The fight had not quite gone out of him, for he is a naturally pugnacious character, but he looked dented and didn’t seem like a winner. Then came the beauty parade of GOP hopefuls, each trying to sound more conservative than the next, who relegated him to the back of the field.

Mr. McCain is used to waiting. After his A-4 Skyhawk was shot down during a bombing run over Hanoi in 1967, he was beaten, taken prisoner, and not released for nearly six years, during which time he was routinely tortured. For two years he languished in solitary confinement. Allowing Messrs. Thompson, Huckabee and Romney to play through while he was stuck in the rough was, for him, a mere inconvenience.

Mr. McCain is used to disappointment. His father and grandfather were both Navy admirals and he dearly wanted to match their achievement. It was not to be. He retooled his career as a politician in Arizona.

He is tough. The quotidian brutality of the Hanoi Hilton guards is not the only dirty fighting he has endured and transcended. In 2000, running for the Republican nomination against George W. Bush, he became the victim of an “anonymous” smear that suggested he had fathered a child with a black woman. (He had, in fact, adopted an orphan girl from Bangladesh.)

He has shown valor on and off the battlefield. Although undeniably a conservative, he has dared try to limit the influence on legislators of lobbyists and big donors. He introduced a line item veto to purge pork spending, only to see it struck down by the Supreme Court. Rather than wallow in xenophobia, he has tried to fix illegal immigration. He condemns water boarding, which he knows to be torture. Having resisted the blandishments of the North Vietnamese, he finds it repugnant to pander. He has taken on the Christian Right, which he believes has had a disproportionate influence upon the Republican Party. As the recipient of the Silver Star, the Bronze Star, the Legion of Merit, the Purple Heart, and a Distinguished Flying Cross, he defended the gallantry of the multi-decorated John Kerry against the sniping Swift Boat Veterans.

Nothing much has changed about Mr. McCain in the months since he fell from favor in the polls. He has shown great patience riding out the neophyte storm. He watched the ghost candidacy of Mr. Thompson come and go. He observed Mr. Romney lavish his personal fortune on the people of Iowa and New Hampshire, to diminishing effect. He has remained silent in the face of Mr. Huckabee’s conspicuous pieties.

He can be excused a sly smile as, slowly and steadily, his persistence has paid off. If there is a single key to his resurgence, it is his typically strident and stalwart support for the job being done by General Petraeus’s troop reinforcements in Iraq. He advocated the surge before the White House came round to his point of view. For a long while, and well ahead of the resulting tumble in casualties, he was a lone voice in defense of the president’s surge policy. He was aware he was staking everything on the courage, fortitude, and efficacy of America’s fighting forces. He had confidence in their success and deserves to reap the benefit.

As those around him trimmed and bowed to siren voices, he has remained resolute. From the start of the Iraq adventure, the senator insisted that we were attempting too much with too few boots on the ground and his sound judgment is at last being rewarded.

The war in Iraq remains the number one preoccupation with Republican voters and they appear to be giving Mr. McCain the credit for clear leadership and doing the right thing. The surge in Iraq has begat a surge in support for him in Iowa and New Hampshire.

Although he had every reason to distrust George W. Bush since the dirty 2000 Republican primary campaign, Mr. McCain has proven to be one of the White House’s most loyal and vociferous allies. He has carried the president’s water over immigration legislation and suffered the consequences without complaint. Mr. Bush’s decision to stay above the fray until after the GOP has chosen its candidate has meant remaining silent over Mr. McCain’s efforts on his behalf.

Nonetheless, Mr. McCain finds himself in an enviable position. Unlike Mr. Romney and Mr. Huckabee, he need only do better than expected in the sudden death states of Iowa and New Hampshire to be credited with momentum. If he were to win either, it would make him a most formidable contestant in the first great primary showdown on February 5.

The Republican Stakes are too close to call, but Mr. McCain is well placed to come out on top. Having been an early favorite to win, the senator now has that most American of narratives to fulfill: the former favorite son who falls into disfavor, then comes from behind to win. It would be a Hollywood ending for a military hero straight out of a movie.

nwapshott@nysun.com