(CBS) -- The race for the Republican presidential nomination is about to turn national, and the candidates Wednesday night have their last, best opportunity to make their case to the country's conservatives.
Wednesday night's debate, hosted in Mesa, Arizona by CNN, will mark the first debate in nearly a month and the last before two key states vote on Tuesday, February 28: Arizona and Michigan. It's also the last debate before "Super Tuesday" on March 6, when 10 states will weigh in and a whopping 437 delegates will be at stake. A candidate needs 1,144 delegates to win the nomination -- check out the current delegate count here.
Since the last debate on January 26, the campaign has taken multiple dramatic turns. Former Massachusetts Gov. Mitt Romney won the Florida primary, prompting speculation that he could quickly secure the GOP nomination. Then former Sen. Rick Santorum turned the race on its head by sweeping three nominating contests two weeks ago. Former House Speaker Newt Gingrich's campaign has stalled, though it could soon get a big boost as one wealthy Republican plans to give a significant sum of money to a pro-Gingrich super PAC, and Rep. Ron Paul continues to collect delegates and put up healthy fundraising figures.
Yet with all of those developments, voters still seem dissatisfied with the race and the GOP field. In a Gallup/ USA Today poll released Monday, 55 percent of Republicans nationwide said they wished someone else were running, while 57 percent said the tough primary isn't hurting the party.
National perceptions are now more important than ever, since the candidates can't devote large sums of time or money in Super Tuesday states. Gingrich in particular has looked to Super Tuesday -- when his home state of Georgia votes -- to bring about his latest campaign revival. Gingrich may also stand to benefit the most Wednesday night, since he has proven his rhetoric can bring a debate audience to give him a standing ovation.
Gingrich on Tuesday played down the importance of this debate, but on Friday, the candidate berated his rivals for declining to participate in a March 1 debate.
The Wednesday debate could also impact the results in Arizona or Michigan, possibly upending things for Romney or Santorum.
In Arizona, Romney has long held the lead, but the latest poll from CNN gives the former governor just a four-point edge over Santorum -- within the poll's margin of error.
Santorum has the lead in Michigan, but the latest polls suggest Romney is closing in on him. A loss in Michigan could be devastating for Romney, who was born and raised in the state. His ties to the state -- and his 2008 primary victory there -- have left expectations there undeniably high. Romney himself is responsible in part for setting high expectations: In an interview with Michigan reporters, when asked whether he could lose the state, Romney said, "Well, that won't happen."
In order to turn things around in Michigan, Romney will have to use the Wednesday debate to amplify the themes he's pushed in his campaign ads and on the stump. The former governor has cast Santorum as a Washington insider who lacks fiscal conservative credentials. He's also worked to build up his personal image with voters, playing up his ties to the state.
Santorum, meanwhile, will have to prove to voters that he's ready to take the main stage against President Obama. Even though Republican voters favor him, this week's USA Today/ Gallup survey showed that more than half of Americans think Romney is the most electable GOP candidate.
In order to do that, Santorum will have to shift the focus from social issues -- which he's known for -- back to his message of economic populism. However, it's likely Santorum will have to field questions on the several social issues he's confronted in recent days, like prenatal screening or Mr. Obama's "world view."
All the candidates will almost certainly have to broach the topic of insurance coverage for contraception. While that topic will distract from issues that matter more to voters, like the economy, it will at least give them a clear avenue to attack Mr. Obama's health care reforms.
The candidates' Christian beliefs may also come into play since the debate takes place on Ash Wednesday.