LONDONDERRY, N.H. - This was supposed to be the strongest Republican presidential field in memory, but with two days remaining before the New Hampshire primary, cracks are showing.
Each of the top three finishers in Iowa - Sen. Ted Cruz (Texas), billionaire developer Donald Trump and Sen. Marco Rubio (Fla.) - will begin the final push here with important questions surrounding their candidacies. Trailing them are three governors whose campaigns have not lit up the GOP's restless and disaffected grass roots.
Republicans look at the other side and see flawed Democratic candidates: in Hillary Clinton, a former secretary of state who lacks the trust of many Americans, and in Sen. Bernie Sanders (Vt.), a democratic socialist who would be the most liberal nominee since 1972, when George McGovern lost in a landslide. That's some comfort to Republicans - but only if they can find their strongest candidate for a general election.
Saturday's GOP candidates' debate was the most potentially damaging for Rubio, whose performance was widely considered his worst of the campaign. He withered in the face of unyielding attacks from New Jersey Gov. Chris Christie and drew attention to the biggest question about his candidacy: Is he ready to be president?
The battering came at a moment when Rubio was viewed as the candidate on the rise coming out of Iowa. He won the night, if not the vote, in Iowa with some well-executed stagecraft, appearing before Cruz got to claim victory and acting as though he were the winner.
Rubio has been campaigning in New Hampshire with confidence and drawing big crowds, including one Sunday morning at a high school in Londonderry. At that event, he blew past the debate performance with barely a nod, saying that, despite being criticized for being repetitious in his attacks against President Barack Obama, he will continue to repeat them at every stop.
The debate was just two hours in the arc of a longer campaign here, and he could hold on and finish ahead of all of the governors - Christie, Ohio Gov. John Kasich and former Florida Gov. Jeb Bush.
Rubio strategist Todd Harris sounded a defiant note Sunday in the face of the overnight criticism, saying he doubts the debate will have any impact on Tuesday's results.
"Let's take a look at what actually happened in that moment," he said. "Marco said repeatedly what every Republican primary voter deeply, deeply believes, which is that Barack Obama is attempting to fundamentally change the kind of nation that we are. The media may not like us saying that over and over again, but it's the core of our message and we're not going to stop talking about it."
How much the debate will affect Rubio's standing on Tuesday is anybody's guess. But even if he does well, the question about his readiness - to serve as president and to go up against Clinton, if she is the Democratic nominee, will linger.
Trump continues to lead the polls in New Hampshire and could be on track to score his first victory of the campaign. That would put some wind at his back heading into what is likely to be a raucous primary in South Carolina on Feb. 20.
A week ago, there was talk that if Trump won Iowa and New Hampshire, he could be on an unstoppable march to the nomination. That talk has cooled, but he could put his campaign back into high gear with a big victory Tuesday.
That, however, wouldn't settle the question of his ultimate strength as a candidate. What lurks beneath the hoopla of the candidacy is the reality of GOP voters' resistance to him becoming the party's nominee.
Trump has been the master of the media, a reality TV star who knows above all how to dominate modern political communication and commentary. It was that skill that vaulted him to the top of the polls. Since the Iowa caucuses, Trump seems a far less dominant politician.
A few weeks ago, it appeared as though there was something between acceptance and resignation within the GOP establishment about the possibility of a Trump nomination. Today there is considerable resistance to his candidacy among those elites and many rank-and-file Republicans.
In a field of a dozen candidates, Trump's support has looked daunting. His followers are intensely loyal. But advisers to other candidates think that in a smaller field he will be a far more vulnerable opponent, exposed on issues and less able to hector a rival into silence, as he tried with Bush without real success on Saturday night.
There was a little-noticed finding in the last Des Moines Register-Bloomberg Politics poll in Iowa a week ago. Given the choice between Trump and Cruz, in a hypothetical two-person final for the nomination, Cruz trounced Trump by 53 percent to 35 percent.
That represents a flashing yellow light for Trump. Is he capable of expanding his appeal or is he at or near his ceiling?
Because of his Iowa win, Cruz has earned his pass to South Carolina, regardless of his finish here. But his post-Iowa victory lap has been marred by controversy.
Cruz has been dinged for campaign dirty tricks against rival Ben Carson. On the night of the caucuses, his aides undertook what appeared a brazen attempt to dissuade Carson supporters from voting for him by suggesting he was quitting the race.
Cruz offered a lawyerly defense of his campaign's actions, blaming media reporting for the mistake. He also apologized to Carson. But the low-key retired neurosurgeon sliced apart Cruz's defense with a quiet but deadly response that completely undermined the senator's argument.
Cruz's goal has been to consolidate the entire conservative coalition - evangelicals, tea party activists and the smaller pool of libertarians. Getting into a fight with Carson won't help him do that.
In Iowa, Cruz won 34 percent of the evangelicals, who made up 64 percent of the electorate. Among non-evangelicals, he got just 18 percent and ran behind both Trump and Rubio. He won 44 percent of the 40 percent of Iowa Republican caucus attendees who described themselves as very conservative but just 19 percent among the 45 percent who called themselves somewhat conservative.
Cruz has argued that he is a conservative candidate unlike others who have won Iowa only to stumble later. He says he has the money and infrastructure to wage a longer and more successful campaign. But can he truly consolidate the hard right? Can he prosper in states where the share of evangelicals is below 45 percent or 50 percent?
Advisers to Bush, Christie and Kasich were ebullient after Saturday's debate. They now have just two days to capitalize. The fact that these candidates have been struggling to break out only highlights their limitations.
The nominating contest has a way of sorting out questions. The eventual nominee will look stronger by June than any of the GOP candidates look today. But on the eve of the nation's first primary, it's not clear which of them will rise to the challenge.