For the past week, much of the focus of the Republican presidential race has centered on the consequences Mitt Romney will face if he loses Michigan’s primary. After a debate in Arizona on Wednesday, the question should be: What will happen if he wins his home state?

Polls in Michigan show a tight race between Romney and former senator Rick Santorum (Pa.). Romney won Michigan four years ago, but there’s no guarantee he will do so again on Tuesday. A Santorum victory would be a major setback for the former Massachusetts governor, throwing the GOP race into further chaos.

But the contest in Michigan appears fluid. Santorum held a healthy lead shortly after winning Colorado, Minnesota and Missouri. A new round of polls in the past few days showed his margin narrowing from a week earlier, the result perhaps of the negative ads Romney and the super PAC supporting him have been running.

Romney’s aggressive attack on Santorum’s record during Wednesday’s debate — on his support for earmarks, his votes to raise the nation’s debt limit, his support for the federal No Child Left Behind bill and other issues — could further erode the former senator’s standing between now and Tuesday. That would give Romney the opportunity to pull out a victory in Michigan. He is in a stronger position now to win Tuesday’s other prize, Arizona. Santorum has picked up support in the past two weeks, but up to half the voters have already cast ballots, and Romney appears to be in the lead among them.

How much would a pair of victories be worth? Republican strategists say that although they would restore Romney to front-runner status in the race, they could still leave the party looking at a long nomination battle. They also say that winning both states Tuesday wouldn’t be enough to resolve many of the doubts that still surround Romney.

Although he has long been seen as the candidate to beat for the nomination, Romney has fought to meet the expectations that go along with that status. He has been losing that battle of late. Against a relatively weak field of opponents, he has not been able to demonstrate consistent superiority. He has struggled to excite the Republican Party’s conservative grass-roots base. Conservative elites have been critical of his message and his candidacy. His shortcomings have engendered considerable talk about the still-remote possibility of another candidate entering the race.

“I think he would remain in the driver’s seat if he wins, but this campaign season has seemed to be momentum-proof, so [victories next week] will only last until Super Tuesday, when he will need another strong showing,” said Mike DuHaime, a Republican strategist and adviser to New Jersey Gov. Chris Christie. “Given his background in Michigan and his family roots, he is expected to do well, which sometimes limits the momentum, as we saw after a convincing win in New Hampshire.”

Even if Romney were to win Michigan and Arizona, he will face a difficult landscape on Super Tuesday, March 6. A victory in Michigan would boost his prospects in Ohio, but Santorum, who is from neighboring Pennsylvania, is a serious threat there. Former House speaker Newt Gingrich is focused on Georgia, the state he represented in Congress. Tennessee and Oklahoma will be more than problematic for Romney, given their conservative electorates.

“This is going to be a grind. Romney’s team gets that and is prepared for it,” said Phil Musser, who was a top adviser to former Minnesota governor Tim Pawlenty and is now a Romney supporter. “If he ends up winning Michigan and Arizona, that would be a great boost, but I suspect the conservative punditocracy will simply move to establish a new do-or-die narrative for Romney related to Super Tuesday. It’s not fair, but it reflects the recent contours of the race and the unsettled state of the GOP.”

Throughout the campaign, Rom­ney has often performed well when he needed to most. He did better in Iowa than many Republicans first thought he would. He captured the primary in New Hampshire, a must-win state, by an impressive margin. He lost South Carolina, but no one ever thought that state would be friendly to his candidacy. He responded to that loss with a big victory in Florida and followed that with an even bigger margin in Nevada.

He has been the field’s most consistent performer in debates. Only Gingrich has come close. The former speaker got the better of him in a pair of forums in South Carolina, but more by the strength of several standout moments challenging the moderators than because of serious missteps by Romney.

When he has been threatened by one or another of his rivals, he has used the debates to knock them down. He did that first against Texas Gov. Rick Perry in September (aided by the governor’s own mistakes). He outshone Gingrich in two Florida debates when he needed to rebound from South Carolina. On Wednesday, he overpowered Santorum in a forum that was as important for him as it was for the former senator.

And yet the doubts exist for good reason. He has been forced to rely heavily on negative ads, rather than a positive message, to win key battles. He let Colorado, Minnesota and Missouri slip away to Santorum earlier this month. No delegates were awarded in those contests, but the perception of vulnerability those losses created has been a major blow to Romney’s candidacy. He has not been able to connect consistently with conservatives.

As a result, the primaries and caucuses have left him weakened. “The drawn-out process has hurt him long term,” said one strategist, who spoke on the condition of anonymity to offer a candid assessment. “The president’s numbers are improving and his are worsening, stoking fears about his chances in the general election.”

Tuesday will present Romney with an opportunity to turn things back in his direction, although as Republican pollster Whit Ayres noted, margins could be important. “If it’s a squeaker, then the questions and doubts continue,” he said. “But if he wins Michigan by double digits, especially if combined with a double-digit Arizona win, then all the chatter will die down just like it did after Florida.”

Still, Tuesday’s contests will hardly settle things. GOP strategist Gentry Collins, who ran Romney’s 2008 Iowa campaign, said victories would help build Romney’s delegate lead and give him a psychological boost. “But he does so under the dynamic that his opponents will not have sustained a knockout blow,” he said. “Even with Romney restored as the front-runner, there is still room for a non-Romney candidate, if one of these other guys could unify that vote.”

Whether that happens could depend on the results of Super Tuesday. “It’s going to get tidied up very quickly, or it’s going to go on,” said Sara Fagen, who was White House political director under President George W. Bush. “He has to do very well on Super Tuesday. He doesn’t have to win every state but . . . you have to see real growth in his delegate lead.”

Romney certainly needs to win Michigan to put himself back on course. But he needs victories to start coming consistently and by healthy margins. His team is correct that this will be a battle for delegates, but Republicans want a standard-bearer who can do more than scratch out the nomination by attrition. That’s why Tuesday’s contests loom so large.