Wednesday night may well be the season finale of this year's great American reality TV show: The Republican presidential debates. CNN canceled a scheduled March 1 debate in Atlanta after Mitt Romney, Rick Santorum, and Ron Paul pulled out, leaving Wednesday's CNN-sponsored debate in Mesa, Ariz., the 20th of the campaign, as the final debate on the calendar. A lot has changed in the month since the four GOP finalists last squared off in Florida, and while "it's easy to hype any debate as a make-or-break moment," says Howard Kurtz at The Daily Beast, this really is "the last shot the candidates will have at engaging before a national audience." How will each candidate use this opportunity? Here, five predictions:

1. All eyes will be on Santorum
Santorum is, for the moment, "the de facto frontrunner" in the GOP field, and how he handles his "first appearance on the hot seat" could determine his electoral hopes, says Maggie Haberman at Politico. He'll face attacks from Romney and hard-hitting questions on his socially conservative views from moderator John King. In past debates, "Santorum has proven how hard he can hit back," and he could win over Wednesday's GOP crowd by attacking King and the media as anti-conservative. "Umbrage at the moderator worked for Newt," says The Daily Beast's Kurtz. Let's see if Santorum can pull off the same stunt.

2. Mitt will go after his new top rival
Romney needs to stop Santorum's surge, and take him down a peg, says Alan Schroeder at The Huffington Post. By highlighting Santorum's broadly unpopular views on hot-button social issues, Mitt can make voters see his rival as "a pious village elder of 17th century Salem in his tall Puritan hat and black robes." But more than that, says Politico's Haberman, Romney needs to "demonstrate some sense of passion, and an ability to connect with the working class." The problem: The more passionate Romney gets, "the more hollow and phony he sounds," says Robert Robb at The Arizona Republic. "Romney probably has no choice but to systematically dismantle Santorum the way he dismantled Newt Gingrich."

3. Newt will try to recapture his debate magic
"Debates are usually terra firma for Gingrich, who has an instinct for the jugular and a way of channeling the anger and frustration of the Republican right," says Candy Crowley at CNN. But that fiery Newt was AWOL during the last two debates. Now, "Gingrich needs Santorum to collapse under the weight of expectations for a frontrunner." Clearly, political scientist Audrey Haynes tells The Arizona Republic, Newt "has the most to lose" Wednesday night, "because if he does not come back now, his momentum and gravitas are gone for good."

4. Ron Paul will just be Ron Paul
Unlike his rivals, "Paul has not chosen to make the debates his proving grounds this cycle," says Politico's Haberman. The Texan is likely to continue his attacks on Santorum over his Bush-era fiscal record, lending an assist to Paul's friend Romney. And remember, Paul has already done much to "increase the market share of libertarian views in Republican politics," says The Arizona Republic's Robb. On Wednesday, he should "advocate his non-interventionism" in an attempt to woo those independents and the "reasonably large swath of Republican voters" who don't like "the bellicosity of Republican political leaders on foreign policy."

5. John King will likely play some local wild cards
Immigration will "inevitably" come up as a local Arizona issue, says Robb. And it's hard to see how CNN can resist asking about "Republican rising star and border-security hawk" Paul Babeu, the Pinal County sheriff who, until Saturday, served as Romney's Arizona campaign co-chairman, says Dan Nowicki at The Arizona Republic. After a local paper accused Babeu of threatening a Mexican ex-boyfriend with deportation — he denies misconduct — the sheriff came out as gay and quit the Romney campaign. "Romney can consider himself lucky if Babeu's name doesn't come up at the forum."