As Republican voters in Arizona and Michigan head to the polls Tuesday to make their mark on the prolonged GOP presidential nomination race, recent surveys show former Massachusetts Gov. Mitt Romney and former Pennsylvania Sen. Rick Santorum neck-and-neck in Michigan, with Romney holding a double-digit lead in Arizona.
Campaigning for both men has focused mostly on Michigan, where Romney has clawed back from trailing Santorum in polls over the last couple of weeks, and experts say it's a critical turning point in the road to the nomination.
"[The race] starts petering out after Michigan, the scenario is almost mind-boggling right now to figure out how Santorum could win this, just by looking at the plain math," says Taylor Griffin, former senior advisor for John McCain's 2008 presidential campaign and partner at Hamilton Place Strategies.
"Romney probably wins Michigan tomorrow and then we go on to Super Tuesday," he says. "You can't beat him on organization, money and the amount that he can put out on the air and the inevitability card wins over and ultimately everyone gets behind not Romney, but beating Obama."
Griffin says Romney's strength in Michigan as elsewhere is his focus on economic issues. Romney is also not hurt as much as some thought he would be among GOP voters for his position opposing the auto bailout implemented by President Obama, as recent polls show Michigan voters split in their support of the effort. The key to a Santorum victory would lie in generating high turnout in rural Michigan, where the voters are more motivated by social issues.
Kyle Kondik, political analyst with the University of Virginia Center for Politics, agrees that Romney is still the likely nominee.
"Romney's not exactly setting the world on fire, but he does seem to still be in decent shape," he says. "I do think a Romney loss would not look good, but so long as he wins, I think he gets positive momentum out of it because also Arizona is happening."
Kondik says Romney's support in Arizona is buoyed in part by the state's Mormon population, which heavily favored him in the 2008 contest.
"There's also a not-insignificant Mormon population, I think it was 11 percent of the GOP primary electorate in 2008 that was Mormon," he says. Kondik added that exit polling at the time showed that about 80 percent of those voters cast their ballot for Romney, a Mormon.
Shane Wikfors, spokesman for the Arizona Republican Party, says voters in the Grand Canyon State are like those across the country and are mostly concerned about jobs and the economy.
"Many voters think there is an integration of the illegal immigration issue into the economic issues, but overall our voters are concerned about jobs and the economy," he says. "I think everybody at this point is starting to get fatigued with the election and there's almost kind of a sense in the air, let's hurry up and get our nominee chosen so that we can get on to the general."
Arizona's primary is closed, which means only Republicans can weigh in. In Michigan, however, the GOP primary is open to all voters, including Democrats. Some have said they plan on casting their ballot for Santorum, who is viewed by many Democrats as a weaker opponent to President Obama in the fall because of his conservative positions on social issues, such as abortion and birth control.
But Kondik dismisses this as a potentially significant factor in the primary's outcome, even though the race appears to be close.
"There's some research basically showing that when you hear about these people crossing over to vote in the opposing party's primary that it usually doesn't amount to all that much," he says. He adds that such a move would only matter in a very close race, one decided by a margin of less than two percentage points.
"If Santorum wins, then maybe there was some impact there. But it's unlikely that there's going to be a big crossover vote for Santorum," Kondik says.
The two other GOP contenders, former House Speaker Newt Gingrich and Texas Rep. Ron Paul, are still factors in the race, Kondik says, even though they are not expected to come close to winning in either state.
"They're relevant in the sense that they are taking a combined 20 or 30 percent of the vote," he says. "This thing could go on for quite awhile here, but the path to victory is a lot clearer for Romney than it is the others."
Paul, Romney and Santorum are all scheduled to campaign in Michigan Tuesday, while Gingrich will be in his home state of Georgia, meeting with voters there ahead of next week's Super Tuesday primary.
- See U.S. News Weekly: an insider's guide to politics and policy.
- Read: Detroit Residents Bash Romney in New Ad.
- Follow U.S. News Debate Club on Twitter.