5 things to watch in the Republican debate

Trump steps up New Hampshire ground game
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Story highlights

  • Donald Trump is back on the stage, and under pressure, as Republicans meet for their final debate before Tuesday's New Hampshire primary
  • Trump isn't the only candidate under pressure -- three governors whose hopes of breaking out of the second tier are riding on their results here will be on the attack
Donald Trump, Hillary Clinton, Bernie Sanders, John Kasich and Chris Christie join Jake Tapper for a special, commercial-free edition of "State of the Union" Sunday at 9 a.m. ET.

Manchester, New Hampshire (CNN)Donald Trump is back on the stage, and under pressure, as Republicans meet for their final debate before Tuesday's New Hampshire primary.

The real estate mogul, knocked down by Texas Sen. Ted Cruz in Iowa, will attempt to regain his footing in a debate set for 8 p.m. ET Saturday on ABC.
But Trump isn't the only candidate under pressure. Three governors whose hopes of breaking out of the second tier are riding on their results here will be on the attack.
    Here are five things to watch Saturday night:

    1. Cruz's Carson problem

    The Cruz campaign's decision to suggest in the midst of the Iowa caucuses that Ben Carson was dropping out of the presidential race is causing the candidate headaches in New Hampshire.
    Trump accused Cruz of stealing his win in the caucuses. Florida Sen. Marco Rubio, the third-place finisher, said it's yet another example of a politician willing to do anything to win.
    The controversy isn't going away -- in large part because Cruz's top opponents won't let it.
    Rubio even joked about it Friday at a campaign stop in Derry.
    "If you get a call on Tuesday night saying I dropped out, it isn't true. It's a lie. Don't believe it," he said.
    Keep an eye on Carson himself -- a mild-mannered candidate who hasn't attacked in previous debates.
    The former neurosurgeon has denounced the Cruz campaign's moves in moral tones and has just gone through a painful process of paring back his own staff. He says he's now ready to stay in it through the convention.

    2. Trump's second act

    So much of presidential politics is about momentum -- and momentum comes when a candidate is able to beat expectations. It's why Rubio seemed to emerge a winner in Iowa, even though he'd only come in third.
    Trump, conversely, has stumbled in the expectations game.
    He spent months on the campaign trail reading off his own poll numbers -- citing them to demonstrate how strong he was and how weak his opponents must be.
    Chastened by Iowa, Trump has choices to make. Will he soften his tone, as he has in some post-Iowa appearances? Will he pretend Iowa never happened and crow about his hefty lead in New Hampshire polls? Or will he double down on his charge that Cruz stole a victory in the Hawkeye State through dirty tactics?
    Above all, Trump will need to convey strength in the face of adversity. It's the selling point his supporters have admired most about him.

    3. Get Marco

    It's tough to overstate what bad news Rubio's surge in Iowa was for at least three other candidates: former Florida Gov. Jeb Bush, New Jersey Gov. Chris Christie and Ohio Gov. John Kasich.
    Florida Sen. Marco Rubio's polling surge puts him in the firing line as his Republican rivals battle for survival in the final GOP debate ahead of the Granite State's primary on Tuesday.
    Each is competing for the mantle of the GOP "establishment" preference and has pinned his hopes on New Hampshire, a New England state that has fewer evangelical voters and allows independents to vote in primaries, as the place to break out.
    Rubio just about stole that opportunity from them before they even got it.
    So he now finds himself under a barrage of super PAC attack ads because, while Trump and Cruz might sit at the top of the Republican pack nationally, Rubio is the roadblock that keeps anyone else from rising into the top tier of candidates.
    It won't just be Cruz and Rubio sparring over immigration and stylistic differences in the Senate this time.
    Particularly keep an eye on Kasich, whose poll numbers in New Hampshire show he could be the most likely to break out of the governor pack, and Christie, who's turned in some strong debate performances and hasn't been afraid to take on Rubio in person.

    4. The governors

    Bush, Kasich and Christie know their fate hinges on New Hampshire's results: There aren't three tickets for governors out of the Granite State's primary.
    The state's more moderate leanings make it sturdier ground for "establishment" candidates, leading all three to build their campaign strategies around a solid finish here.
    It won't be enough to take on Rubio. The super PACs supporting the three have traded shots on the airwaves, but the candidates will need to be sharper on the debate stage in their last high-profile chance to reach a national audience before Tuesday's primary.
     Trump and Cruz find common ground on 'Trumpertantrum'
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    Trump and Cruz find common ground on 'Trumpertantrum' 02:00
    Each is desperate for a breakout moment that could help him win over New Hampshire voters who have historically made up their minds at the last minute.

    5. Cruz's play

    The last time Republicans debated, four days before the caucuses, Trump wasn't even on the stage -- so Cruz was the one taking most of the heat as the other leading front-runner in Iowa polls.
    Now that he has won a state, Cruz has fully dropped the niceties toward Trump. And the two could mix it up for the first time on truly equal footing.
    Front-runner status can be a handicap, but Cruz has one huge advantage in the debate: Evangelical voters make up far less of the electorate in New Hampshire. That means he's probably not going to win the state -- and if the road to victory doesn't run through him, the lower-polling candidates have less to gain by attacking him.
    Cruz could use the debate to make a play for the next state, South Carolina, where evangelical voters make up a larger share of the GOP electorate and which is next to vote, with its primary on February 20.
    His strategy has long involved picking up delegates in Southern states that vote in early March, too -- so his message won't need much change.