Crunch Time: What GOP Candidates Need to Prove at the New Hampshire Debate

— MANCHESTER, NH -- Iowa has sent New Hampshire voters a gift, of sorts: a slightly winnowed field.

Rand Paul’s departure this morning marked the third campaign to call it quits since the caucuses. But several others are calling the New Hampshire primary a do-or-die moment, and in a still-crowded Republican field, Saturday’s primetime GOP debate may represent the last chance for candidates to make their pitch, and inflict damage on their opponents.

So where will we see fireworks?

Trump and Cruz

The stakes are high for Donald Trump, who saw his slight lead in Iowa disintegrate into a second-place finish. While the New York real estate mogul delivered a gracious concession speech, he erupted this morning. He accused Texas Sen. Ted Cruz of “stealing” the caucuses by using deceptive mailers, and convincing conservatives that Ben Carson was dropping out of the race.

It’s beyond unlikely that Trump will get his wish, so a debate brawl might be the next best thing.

The Cruz camp seems ready for it. In a statement, spokesman Rick Tyler said “reality just hit the reality TV star – he lost Iowa and now nobody is talking about him, so he’s popping off Twitter. There are support groups for Twitter addiction, perhaps he should find is local chapter.”

Cruz and Rubio

Cruz won the caucuses, but Florida Sen. Marco Rubio arguably won the news cycle. His stronger-than-expected performance vaulted him to the top of newscasts, where he took the opportunity to needle Cruz.

“Basically, his entire campaign is an Iowa campaign,” Rubio told ABC News during a lunch break Tuesday. “We’ve been running a full-time campaign everywhere.”

Cruz, meanwhile, was zig-zagging the country Tuesday, giving an impromptu news conference aboard his plane, “Constitution One.”

Asked about Rubio, Cruz demurred. “Where I’m going to keep my focus, is my positive optimistic conservative message,” he said.

The two have sparred repeatedly over immigration and national defense. Expect each of them to appeal to Granite Staters to give them a second or third look in the wake of their success.

Rubio and Everyone Else

The Rubio campaign has declared it a “three-man race” between Rubio, Cruz and Trump.

Don’t tell that to Jeb Bush, Chris Christie or John Kasich, who have staked their political lives on a strong finish in New Hampshire. The three governors have launched an all-out blitz against the now high-flying Rubio.

New Hampshire voters awoke this morning to a full-page ad in the state’s largest newspaper, touting endorsements from Florida House speakers who decided to back Bush, not Rubio. Ads from super PACs like Right to Rise, which supports Bush, have put out attack spots focusing on Rubio’s personal credit cards.

New Jersey Gov. Chris Christie, meanwhile, has continued to tie Rubio’s leadership experience to President Obama.

“Fool me once, shame on you. Fool me twice, shame on me,” Christie told a New Hampshire crowd, describing the dangers of promoting a first-term senator to the Oval Office.

Ohio Gov. John Kasich has displayed a relentlessly positive attitude on the New Hampshire campaign circuit, but has shown a willingness to engage on the debate stage. He has also shown a distaste for his rivals’ ads, calling on Bush and Christie to take “negative crap” off the air.

Between Rubio and the three governors, it’s likely only one or two emerge from New Hampshire as the “establishment” alternative to Trump and Cruz. Six days from the primary, more than 20 percent of Granite State Republicans say they’re undecided.

ABC News will announce the lineup for the Republican debate Thursday.

ABC News' Jessica Hopper and Jordyn Phelps contributed reporting.

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