The Republican presidential contenders will square off in Mesa today in a high-stakes debate that promises to set the tone for a crucial stretch of the campaign through the Arizona and Michigan primaries and Super Tuesday. 
 
 GOP frontrunners Mitt Romney and Rick Santorum are locked in tight battles in Arizona and Michigan, two states that vote on Tuesday, and former U.S. House Speaker Newt Gingrich is hoping for a strong showing among the 10 states that will hold nominating contests on March 6. 
 
 Libertarian-leaning U.S. Rep. Ron Paul, R-Texas, is expected to remain a presence in the GOP race until the Republican National Convention in Tampa. 
 
 Today's 6 p.m. debate at the Mesa Arts Center in downtown Mesa is co-hosted by CNN and the Arizona Republican Party. Here are a few things to watch for: 
 
 Romney's tone. The former Massachusetts governor was long considered the clear GOP leader in Arizona, but polls have narrowed considerably in recent days and now indicate a dead heat between him and Santorum. Romney is locked in an unexpectedly fierce battle for Michigan, the state where he was born and where his father, the late George Romney, was a popular governor in the 1960s. If Romney comes out swinging hard against Santorum, it could mean he's worried about his standing in Michigan or Arizona. If Romney tries to come across as more presidential and focuses his fire on President Barack Obama, he's likely feeling comfortable that he has stopped Santorum's surge in Michigan, where a loss would be a major embarrassment. Either way, Romney, who is perceived as too moderate by some Republican voters, will try to make the case that he is a solid conservative. 
 
 "You can expect Romney to unload on Santorum, and Santorum will unload back," said Larry Sabato, director of the Center for Politics at the University of Virginia. "I do think of Michigan as a must-win for Romney, along with Arizona. He just can't afford to lose that." 
 
 The Babeu factor: Pinal County Sheriff Paul Babeu's endorsement of Romney was barely noted when made, but now, the embattled lawman has become an issue in the 2012 presidential campaign. Babeu's office and congressional campaign were rocked late last week by accusations that the Republican rising star and border-security hawk may have abused his power by threatening a former boyfriend. Babeu denies the allegations of misconduct but publicly acknowledged for the first time Saturday that he is gay. The Mesa debate is being held as news about the scandal dominates Arizona headlines. Nationally, much of the coverage has focused on Babeu's decision Saturday to step down as Arizona co-chairman of Romney's campaign. Romney can consider himself lucky if Babeu's name doesn't come up at the forum, but CNN moderators at past debates have not been shy about injecting late-breaking controversies into their line of questioning. 
 
 Can Santorum change the subject? Santorum has been on the defense against his opponents' characterization of him as a zealot on religious and family issues. The widely read Drudge Report website on Tuesday carried a main headline screaming "Santorum's Satan warning," related to remarks the former U.S. senator gave in 2008 in which he said the devil "has his sights on the United States of America." Santorum also has drawn scrutiny and criticism for recently attacking Obama for following a "phony theology" that is not based on the Bible. His spokeswoman, Alice Stewart, fed the storyline with a gaffe on MSNBC in which she mistakenly referred to Obama's "radical Islamic policies." Obama is a Christian. In a third incident, a Santorum surrogate made an ill-advised joke about contraception. With Santorum reaching for authentic national front-runner status, he can't afford to be typecast as a fringe social conservative. 
 
 Gingrich's last stand? Gingrich, a former top contender who has wilted under a barrage of Super PAC advertising since winning the South Carolina primary in January, has relied on debates to revitalize his fortunes before. He is not afraid to bash his media interrogators, which reliably earns him cheers from conservatives who are suspicious of liberal bias in the news. "He does well in debates, and it gives people a chance to see beyond the $20 million in negative ads that have been run against him," said former U.S. Rep. J.C. Watts, R- Okla., a Gingrich campaign surrogate. If Romney and Santorum get nasty with each other, Gingrich might have the opportunity to take the high road and, as he likes to do, present himself as the visionary candidate with big ideas and solutions. 
 
 John King's moderation. The CNN news anchor and chief national correspondent will run the show. King was the moderator at the Jan. 19 debate in Charleston, S.C., who was excoriated by Gingrich after he brought up allegations made by Gingrich's ex-wife. King drew some criticism at the time for not pressing Gingrich harder. "I would be surprised if John were not more aggressive if he (Gingrich) were to try to do the same thing again," said Whit Ayres, a Republican pollster based in Alexandria, Va., who worked for former Utah Gov. Jon Huntsman's presidential campaign but is not affiliated with any of the candidates still in the race. 

 There will be four men and one moderator on stage at Wednesday night’s GOP debate in Arizona. But Mitt Romney and Rick Santorum will be the main attractions. 
 
 The CNN-sponsored debate in Mesa — the first one in almost a month — looms as a focal point in a contest that has increasingly been recast as a two-man fight, with polls showing tight upcoming contests between Romney and Santorum in Arizona and Michigan. 
 
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 reset VandeHei on Santorum tonight Best of Florida debate Best of South Carolina debate 
 
 The setting in many ways favors Santorum, who has tended to get the better of Mitt Romney in their exchanges in past debates. The X factor is Newt Gingrich, who may be tempted to ditch an easy chance to let others throw punches and instead try to claim the spotlight in a format that — at least until Florida — had proved successful for him throughout the GOP primary. 
 
 Santorum, while less theatrical than Gingrich, is the most agile debater in the current field. But Romney is also strong and has tended to perform at his best when he’s had to come from behind — witness the two Florida debates before the Jan. 31 primary. In those venues, when he needed a command performance, he delivered. 
 
 Their lines of attack are clear: Santorum is certain to hit Romney over the Massachusetts health care plan that was his signature achievement as governor. Romney will fire back that Santorum is an “insider,” the same line he has used to try to dispatch other rivals, and will point to the former senator’s earmarks and other issues that undermine Santorum’s claims of fiscal conservatism. 
 
 For Santorum, the debate will mark his first appearance on the hot seat as he heads into Wednesday evening as the de facto front-runner — and the man under attack from Romney and Ron Paul. 
 
 The difference between Santorum and the other contenders whom Romney has faced so far? Of all of them, Santorum has proved how hard he can hit back on stage and drive to keep punching. 
 
 “We believe Romney’s very good at what we would call ‘hit and run,’” Santorum adviser John Brabender told POLITICO, adding that he “has a surrogate throw out half a story on Rick Santorum” and then tries to lob shots from a safe distance. 
 
 “There’s no way to hide in a debate where there’s only four people standing on stage,” Brabender said, adding that the campaign doesn’t spend much time preparing for these events. 
 
 “Rick Santorum won’t be the least bit afraid of Barack Obama either,” Brabender said. “You’re not going to just back down when someone disagrees with you. It’s the difference between a forum and a debate. [‘Romneycare’ is] a discussion that is so fundamentally critical to this race, because how do you take Obamacare off the table [in a general election]?” 
 
 Romney, Brabender added, tends to stick with a set of “Pavlovian” responses. 

 Forget March 6; the new Super Tuesday is Feb. 28. 
 
 And if Super Tuesday is now Feb. 28, tonight’s debate in Arizona might as well be called Super Wednesday. 
 
 New polling shows not only is Mitt Romney’s win in Michigan in serious jeopardy, but so is his edge in Arizona’s primary the same day. 
 
 
 
 The CNN/Time/Opinion Research poll out Tuesday showed Romney leading Rick Santorum within the margin of error, 36 percent to 32 percent. 
 
 It all makes the stakes for tonight’s debate in Phoenix about as high as they could be for the erstwhile frontrunner. 
 
 The reasons are legion. 
 
 First, this might be the final debate of the GOP presidential race — or at least, the last debate for a while. There are no other debates scheduled before the real Super Tuesday on March 6, and Romney’s campaign has not committed to a planned March 19 debate in Oregon. 
 
 Indeed, Romney’s campaign looks as though be done with debates altogether, citing the overwhelming number of them in declining to attend a scheduled forum in Georgia next week. That debate fell apart, and without Romney, future debates would as well. 
 
 Second, while a loss in Michigan would represent a major setback for Romney — given that it’s a state he calls “home” — a loss in Arizona would be potentially disastrous. 
 
 Romney’s campaign has been able to make a credible argument that the Feb. 7 caucus losses were aberrations based on low turnout and that it didn’t really try that hard in the three states holding contests that day. That case goes out the window if he loses higher-turnout primaries in two states where he should have the edge. 
 
 While Michigan is his home state, Arizona has a significant Mormon population, and the last state with a significant Mormon population, Nevada, delivered him about 50 percent of the vote and a huge win. 
 
 Third, Romney could also lose the Washington caucuses on March 3, where piecemeal polling has shown a competitive race. If Romney lost there after being swept on Feb. 28, it would be his sixth loss in seven contests heading into Super Tuesday — likely all to Santorum. 
 
 At that point, his status as frontrunner would likely be gone, and it would be Santorum’s race to lose. 
 
 And finally, debates provide an unmatched forum. Romney’s campaign hoped its monetary advantage would save it in Michigan and Arizona, but that hasn’t been the case, at least so far. 
 
 Debates in the presidential race have been the best way to turn the race on a dime. While Romney’s campaign has done its best to try and define Santorum with advertising, he’ll have his best opportunity to bring the fight to Santorum at tonight’s debate. 
 
 The next debate is always the biggest debate. But tonight, it’s doubly true. 
 
 Gingrich to skip Michigan: Newt Gingrich’s campaign has said it would put forth some effort in Michigan, but now that’s no longer the case. 
 
 The Atlanta Journal-Constitution reports that Gingrich no longer plans to visit the Great Lakes State before Tuesday’s primary, and he’s only spending time in Arizona this week because that’s where the debate is taking place. Gingrich is instead focusing almost solely on Super Tuesday in an effort to get his campaign back on track. 
 
 As we wrote last week and in a story in today’s paper, though, this would seem to open the door wide for Santorum to beat Romney one-on-one, whereas Gingrich might have otherwise split the anti-Romney vote. But Gingrich also risked further embarrassment by showing up and then performing poorly. 
 
 Republican voters want a nominee: GOP voters may be drawing out the presidential nominating contest, but they don’t want to drag it out till the convention. 
 
 A new Gallup poll finds that two-thirds (66 percent) of Republicans want their nominee determined before the convention, while less than one-third (29 percent) want the nominee to be determined at the convention. 
 
 Or maybe it’s more interesting that nearly one-third of Republican s would actually like to draw it out that far — something that most in the party establishment see as a nightmare scenario. 
 
 Fixbits: 
 
 Romney makes a curious comment for a Republican candidate: That spending cuts slow economic growth. 
 
 Ann Romney says her husband was hesitant to run for president. 
 
 A top Romney supporter in Arizona expresses his dismay with Romney’s campaign. 
 
 More evidence of Romney’s struggles with working class voters. 
 
 The Supreme Court takes up affirmative action. 
 
 Virginia Gov. Bob McDonnell (R), a potential vice presidential candidate, backs off his support for a bill that would require women to have ultrasounds before getting an abortion. 
 
 Former Florida chief financial officer Alex Sink (D) is talking about a rematch with Gov. Rick Scott (R). 
 
 Donald Trump says he may run as a third-party candidate if Santorum wins the nomination. 
 
 Sen. Richard Lugar (R-Ind.) launches an ad against primary opponent Richard Mourdock. 
 
 Sen. Barbara Boxer (D-Calif.) endorses Rep. Howard Berman (D-Calif.) in his primary with Rep. Brad Sherman (D-Calif.). 
 
 Must-reads: 
 
 “Inside the super PACs money deluge” — Phil Hirschkorn and Laura Strickler, CBS News 
 
 “Mayor Villaraigosa’s Sights Set Beyond Los Angeles” — Adam Nagourney, New York Times 
 
 “Super PAC donors revealed: Who are the power players in the GOP primary?” — Dan Eggen and T.W. Farnam, Washington Post 
 
 Read more from PostPolitics 
 
 How to find the Arizona Republican Debate 
 
 The Fix: 4 ways Santorum is out of step with GOP 
 
 The kingmakers behind the GOP's millions 
 
 Fact Checker: Rick Santorum’s euthanasia fantasy 
 
 Meet Rick Santorum, opinion columnist
– It's been a while, but America's favorite political game show is back. Yes, the Republican presidential candidates will square off in Mesa tonight for their first debate in nearly a month. Here are the storylines in play: The final showdown—The stakes are "about as high as they could be," the Washington Post observes, because this might be the last debate of the GOP primary, and certainly the last before Super Tuesday. And since losses in Arizona and Michigan could be fatal for Mitt Romney's campaign, he has to perform tonight. Rick Santorum on the hot seat—This will be Santorum's first debate as what Politico calls the "de facto frontrunner," meaning he's going to take heat, particularly from Romney. But Santorum has actually proven to be pretty good at counterattacks, and his team is confident—one adviser mocks Romney as easy prey because he sticks to "Pavlovian" responses. Ron Paul, Romney pal—Paul has developed a friendship with Romney and, given that he's never used debates as his major platform, he's likely to have his back in the face of attacks. Newt Gingrich: Mr. Nice Guy?—"Ironically, Newt is in a position to look less negative than Romney or Santorum," one campaign source says, because those two will be beating up on each other. "Newt can rise above it and seem statesmanlike." John King's revenge—Newt Gingrich left moderator John King with serious egg on his face during the Jan. 19 debate. "I would be surprised if John were not more aggressive," one Republican pollster tells the Arizona Republic.