WASHINGTON -- Sen. John McCain, given up for dead a few weeks ago as he ran a cash-starved, disorganized campaign, today is viewed by canny Republican professionals as the best bet to win the party's presidential nomination. What's more, they consider him their most realistic prospect to buck the overall Democratic tide and win the general election. Indeed, if Mike Huckabee holds on to actually win the Jan. 3 Iowa caucuses, the road forward could be clear for McCain.

Mitt Romney's lavishly financed, meticulously organized campaign always has operated with a thin margin of error based on winning Iowa and then the New Hampshire primary five days later. If Romney loses to Huckabee in Iowa, he becomes vulnerable to McCain in New Hampshire. If McCain wins there, he will be favored to sweep through subsequent primaries despite meager finances and organization.

This scenario does not connote a late-blooming affection for McCain among the party faithful. Indeed, he remains suspect to them on global warming, stem cell research, tax policy and immigration controls, not to mention his original sin of campaign finance reform (with authorship of the McCain-Feingold Act). Rather, his nomination would result from him being the last man standing, with all other candidates falling. Rudy Giuliani's baggage is getting too heavy to carry. Fred Thompson never got started. Huckabee's Republicanism is even less orthodox than McCain's and seems unviable beyond Iowa. Romney is burdened with anti-Mormon prejudice and the accusation he is "plastic."

McCain's return from oblivion also suggests a personal determination that was demonstrated during six years of torture and solitary confinement in a communist prison. Beginning the year as the GOP's putative establishment candidate, McCain presided over a spendthrift, ineffective campaign. His decline climaxed, however unfairly, when he came over as the apostle of immigration amnesty. Despite a free fall in the polls and the inability to raise funds, McCain has impressed the political community with six months of tireless grass-roots campaigning.

He never has been popular inside the party, even when it seemed he might be its anointed candidate. He is still bitterly opposed by conservative activists Grover Norquist and Ralph Reed and is anathema to Cato Institute members and other libertarians because of campaign finance reform. His opposition to earmarked pork and his demolition of the corrupt deal between Boeing and the Air Force have not enchanted fellow Republican politicians. Transcending ideology, he draws opposition because he will turn 72 next August.

But when Republicans get together privately, they tend to agree that McCain is the Republican most likely to defeat Hillary Clinton or Barack Obama. Even while some consider the old naval aviator as cranky and hot-tempered, he has not exhibited those negative characteristics in debates. Rather, he exudes a heroic aura that goes beyond managing New York City or the Utah Olympics. That quality is shown in his Christmas card television ad depicting a North Vietnamese prison guard making a cross in the dirt. McCain has managed to support the invasion of Iraq while criticizing President Bush's management of the invasion, and he maintains his fiscal integrity in a pork-driven, spendthrift Republican Party.

Having fallen behind Huckabee in Iowa, Romney has concluded he must stop McCain in New Hampshire. He launched daily attacks on McCain last week after having ignored him for months. Apart from assailing McCain for not being a team player, Romney deplored his votes against Bush's tax cuts. McCain has admitted to me that those votes were a mistake, as Romney confesses he made a mistake in his former support for abortion rights. The difference, Romney insiders insist, is that their man freely acknowledges error.

That faint distinction may not be sufficient to stop McCain in New Hampshire if Romney loses Iowa. That is why McCain is praying for the former governor of Arkansas on Jan. 3. The GOP nominee can be determined by how many Iowa social conservatives that night support a high-tax, big-spending opponent of school choice who is called a member of the religious left by critical Southern Baptists. The Republican Party's internal competition has become as peculiar as the Democrats' used to be.