By MICHAEL FALCONE ( @michaelpfalcone ) and AMY WALTER ( @amyewalter )

MESA, Ariz. - The debate may be taking place here in Arizona tonight, but the audience Rick Santorum and Mitt Romney are really playing for is sitting in Michigan.

The latest polling from NBC-Marist confirms the conventional wisdom on the ground: Romney has a solid lead in Arizona but is locked in a dead heat with Santorum in Michigan.

How key is Michigan for Santorum? At a speech in Phoenix last night, Santorum talked about his goal of reviving the declining manufacturing sector and his ability to put "swing states" like Ohio, Michigan, Indiana and Wisconsin "in play." Not mentioned as a swing state, or really mentioned much at all: Arizona.

To be sure, Santorum does have some momentum on his side here. But, working against him is the fact that a big chunk of voters in the state have already voted.

Almost 200,000 Arizona Republicans, including 167,000 from voter rich Maricopa County, have already turned in their ballots. Those voters may not have all cast their ballots for Romney, but if they voted for anyone but Santorum that's a big help to the ex-Massachusetts governor.

And, unlike Michigan where the airwaves are flooded with super PAC ads, only the pro-Romney group, Restore Our Future, is on television in Arizona.   http://bit.ly/x4mUDP

With the race so close in Michigan, the expectations are high for a high-energy and hard-charging debate. As one campaign operative told us, the debate could be "the tiebreaker."

But, when it comes to the Michigan primary, here's the big question for Romney: What happens when a win isn't a win anymore?

One smart and very plugged in Republican insider tells The Note that the bar for Mitt Romney in Michigan is more than simply winning - he needs to win in decisively.

If Romney loses or beats Rick Santorum by a smaller margin than he beat McCain in 2008, argues this insider, "it reinforces what a weak candidate he is."

Already, says this strategist, everyone he speaks with in donor and business world is asking "who can we convince to run"?

The only way to make that chattering stop is for Romney to exceed or match his 2008 performance. That year Romney bested McCain by almost a 10 percentage point margin, 38.9 percent to 29.6 percent.

If he doesn't, says this top GOP bigwig, there is a "50-50? proposition that someone else gets in.

SANTORUM AND SATAN. ABC's Shushannah Walshe notes that Rick Santorum made a veiled mention last night of a controversy that bubbled up after audio of a speech the candidate gave in 2008 in which he said Satan was attacking U.S. institutions in government and religion made its way around the Internet. "I think the reason we are doing so well is because we are available to the American public, no teleprompters, no speeches … sometimes, I've been told that when you don't read off a teleprompter, they may find a thing or two and say, 'Oh, he said this and he might mean this,'" Santorum said at a rally here. "And the media complains so much about these structured candidates and how they are all so robotic," he said. "And then of course when they have a candidate that doesn't do any of those things they say, 'Oh he's really out there, you have to worry about what he says.' No you don't, because I will defend everything I say." In the speech at the conservative Catholic Ave Maria University in Florida, Santorum praised the Catholic Bishop Samuel Aquila for pledging to deny communion to politicians who support abortion rights and said the matter went beyond politics and was a symptom of Satan's reach in U.S. society. The story was the lead item on the Drudge Report today and the candidate was asked about it after the address to about 250 people. http://abcn.ws/wWg5cP

Chris Christie: Rick Santorum's Satan Comments Are Relevant. Rick Santorum says his 2008 comments that "Satan has set his sights on the United States of America"  are "not relevant" to the 2012 presidential race, but Chris Christie told ABC's George Stephanopoulos on "Good Morning America" today that Santorum is wrong. http://abcn.ws/ylLj5q

"Listen, I think anything you say as a presidential candidate is relevant. It is by definition relevant. You're asking to be president of the United States. I don't think [Santorum's] right about that. I think it is relevant what he says. I think people want to make an evaluation, a complete evaluation of anyone who asks to sit in the Oval Office," the New Jersey governor said. Adding to the religious discussion on the campaign trail, yesterday Santorum said he would "defend everything" he says and Mitt Romney said the Obama administration has "fought against religion." But Christie doesn't think a debate over religion is a conversation the Republican Party wants to engage in. "Do I think it's the things we should be as a party talking about and emphasizing at the moment? No," he said.

 

THE BUZZ

DONALD TRUMP RECORDS ROBO-CALL FOR ROMNEY IN MICHIGAN. Mitt Romney's campaign is hoping that when Donald Trump calls, Michiganders will listen. Trump has recorded a robo-call, paid for by the Romney campaign, which is highly critical of rival presidential candidate Rick Santorum. "This is Donald Trump and I have to tell you that I'm tired of Rick Santorum pretending that he's some kind of DC outsider," Trump says on the call. Trump dismisses the former Pennsylvania senator as a "career politician" who has "never had a job in the private sector." He accuses Santorum of working as a lobbyist before and after serving in Washington. "Rick Santorum is completely entrenched in the Washington culture and he has been for decades," Trump says. (Santorum lobbied for the World Wrestling Federation in the 1980-s and worked as a consultant to several companies after he lost his re-election bid to the U.S. Senate in 2006.) On the robo-call, which will begin on Tuesday, Trump calls Romney an "outsider in the race" who "knows how to handle" China and OPEC - two of Trump's most-frequently cited international bogeymen. "He's a good man, he's working hard" Trump says of Romney. "He will win. You've got to give him that chance." http://abcn.ws/wnjN22

ROMNEY LAST PRESS CONFERENCE: TWO WEEKS AND COUNTING. Mitt Romney has not taken questions from reporters in a press conference for nearly two weeks, the longest stretch he has gone without doing so since early November, ABC's Emily Friedman notes. Romney last held a press conference in Atlanta on Feb. 8, and has not done so again since. Wednesday is the two week mark. In the fall, Romney went more than two weeks in between press conferences, holding one on Oct. 26 in Virginia and not doing so again until Nov. 11 in South Carolina. At the beginning of January, Romney would hold near-daily press conferences, during one stretch holding one on Jan. 9, 11, 12, and 17. Romney has, of course, maintained a public campaign schedule, including town halls and tele-town halls where he solicits questions from voters. He has also done several local news interviews. In contrast, Sen. Rick Santorum held press conferences on Feb. 9, 15 and 18. Newt Gingrich has held four press conferences since Feb. 13. A spokesman for the campaign had no comment. http://abcn.ws/xwm68t

RON PAUL TAKES ON SANTORUM. Ron Paul is once again going after Rick Santorum's record as a fiscal conservative in a new ad, potentially giving Mitt Romney a boost in the process, ABC's Jason Volack reports. The 30-second ad titled "Fake," which follows up a similar ad released in January, blasts Santorum for increasing the size of government by voting  "to raise the debt ceiling five times," "doubling the size of the Department of Education" and for voting "to send billions of our tax dollars to dictators in North Korea and Egypt." The ad even criticizes Santorum for hooking Planned Parenthood "with a few million bucks." The "Fake" ad is scheduled to begin airing this weekend in Michigan, which could provide a valuable boost to Mitt Romney, who is locked in a dead heat with rival Rick Santorum in that state. Ron Paul and Mitt Romney reportedly have a friendly relationship, which Romney has worked to cultivate. http://abcn.ws/zQW3UE

NOTED: The pro-Obama super PAC, Priorities USA, made a $238,000 television ad buy in Michigan from Feb. 22 through Feb. 28. The buy, according to a source tracking ad buys, focuses on broadcast and cable in the Detroit and Flint-Saginaw media markets. Spokespeople for the group declined to release the ad Priorities USA is running.

OBAMA NAMES 2012 CAMPAIGN AMBASSADORS. President Obama's re-election campaign today designated 35 state, local and community leaders as national co-chairs, or "ambassadors" for the president, who will play a high-profile role in defending his record and mobilizing voters for November, ABC's Devin Dwyer writes. The list includes current and former Democratic members of Congress, governors, and mayors, as well as business and labor leaders, members of clergy and a few local campaign organizers, a nod to the value Obama places on his grassroots volunteers. Former White House chiefs of staff Bill Daley and Rahm Emanuel will play key roles. Actor Kalpen Modi is expected to lead outreach to younger voters, while actress Eva Longoria will spearhead efforts to reach women and Hispanics. All are "proud of the president's record and leadership," the campaign said in a statement. Full list of the "ambassadors": http://abcn.ws/xHejgw

 

PRIMARY STATE SPEED READ

by ABC's Elizabeth Hartfield and Chris Good:

-Romney fundraising slips in Arizona. Mitt Romney leads all presidential candidates in fundraising in Arizona, including Barack Obama-but during the month of January, his opponents outdid him. Both Obama and Newt Gingrich outraised Romney in Arizona in January, the Arizona Republic reports. http://bit.ly/x9XzN6

- Will Santorum Wear Ashes? It's debate night in Mesa, Ariz.-and it's also Ash Wednesday. The Arizona Republic's E.J. Montini notes the role of faith in Santorum's campaign and wonders whether the candidate appear on CNN with an ashen cross on his forehead. http://bit.ly/wZ5kgj

- Arpaio: Obama Should Thank Me. Renowned immigration hardliner and Maricopa County sheriff Joe Arpaio, speaking at a Republican event on Tuesday, said he thinks "The president should be thanking me every time we raid a place…I never get any thanks from the White House-that's okay, it doesn't bother me." http://bit.ly/zWxBnN

- Michigan Flooded by Robocalls. Voters in Michigan are tired of phones ring constantly with automated campaign calls, and Detroit Free Press readers tell the paper that most of the calls are coming from Romney or his allies. http://on.freep.com/ztFHHc

- Paul's Brother: Candidate 'All Right' With Trailing. With his brother trailing in polls, David Paul tells The Detroit News that the candidate probably won't win and that "I feel all right with it…He does too." Ron Paul has discussed on national TV the possible impact his campaign could have on the GOP without him winning the nomination and what his second-prize options would be-likely a voice at the national convention in Tampa and a say in the Republican Party platform. http://bit.ly/xH8bkB

- Abortion Becomes a State Issue in Georgia. Good news for the staunchly anti-abortion Rick Santorum? A bill limiting the legal timeline or abortions is quickly moving through the Georgia legislature, the Atlanta Journal Constitution reports: "House Bill 954 would cut the time a woman could have an unimpeded abortion to 20 weeks from about 26 weeks. Proponents say the measure is needed to prevent late-term abortions to fetuses they say can feel pain." http://bit.ly/xAhtD9

-Tennessee Titan: Campaign finance records show donors across Tennessee favoring Romney. Romney has far out-raised the rest of the GOP field in this super Tuesday state, though local political scientists warn that money and votes are two separate issues.  http://tnne.ws/xSrz8n

-Santorum's Math Problem in Ohio: Rick Santorum has a delegate disadvantage in Ohio. The former Pennsylvania senator didn't qualify for the ballot in three congressional districts- meaning he's not eligible for a total of 9 out of Ohio's 66 delegates. Could Santorum win Ohio's primary despite not qualifying for the ballot in three out of Ohio's 16 congressional districts? The Plain Dealer thinks so.  http://bit.ly/xmJOpd

 

WHO'S TWEETING?

@politicoalex : He's baaaack: Herman Cain wades into 2012 congressional races, throws backing to like-minded candidates - my story - politi.co/w0jWH4

@evanmc_s : My and  @BenjySarlin's piece from last night: conservatives start to warn GOP about Santorum's extremism bit.ly/xqkub9

@ZekeJMiller : RT  @nationaljournal: Former Romney debate coach's message to Santorum: The stakes could not be higher  njour.nl/zUenSp

@politicalwire : Bad news for Republicans: Interest in presidential race among GOP voters is slipping…  pwire.at/xbv39U

@SovernNation : Newt's fallen apart in CA. Field Poll says his favor/unfavor now 35/52. Last poll it was 55/22. Mitt is at 66/19, Santorum 40/22, Paul 24/50

 

POLITICAL RADAR

- Mitt Romney, Rick Santorum, Newt Gingrich and Ron Paul are all in Arizona for the CNN Republican debate in Mesa tonight.

- Mitt Romney will also hold a morning grassroots rally in Chandler.

- Rick Santorum will address a Tea Party rally in Tucson.

- Newt Gingrich and his wife, Callista, will make a stop in Scottsdale to meet supporters at a debate watch party. Callista will also hold an event of her own in Gilbert, where she will read to local elementary school students.

- Ron Paul will host campaign fundraisers in Mesa.

ABC News' Joanna Suarez

 

Check out The Note's Futures Calendar:  http://abcn.ws/ZI9gV

 

* Get  The Note delivered  to your inbox every day.

* For breaking political news and analysis check out The Note blog:  http://blogs.abcnews.com/thenote/ and ABCNews.com/Politics:  http://abcnews.com/politics