The potential for drama among Republican presidential candidates is running high as they gather Thursday in South Carolina for a debate that will set the stage for the final burst of campaigning before the voting begins in Iowa. Here are five things to watch:
Can anything break Donald Trump's momentum?
With his blunt and sometimes vulgar approach to campaigning, the New York billionaire has built a following that has only grown over the last six months. He hurls insults at rivals and critics with abandon, but has proved immune, so far, to attacks. With pressure building on the six opponents who will share the stage with him in North Charleston, could one of them finally trip up Trump?
How aggressively will Trump and Texas Sen. Ted Cruz go after each other?
Both have a strong incentive to go on offense as they fight for the bragging rights of a victory in the Iowa caucuses. Trump may hold a double-digit lead over Cruz nationally, but the two are tied in Iowa, which kicks off the nomination contest on Feb. 1. Trump has been questioning whether Cruz's birth in Canada to an American mother makes him unqualified for the presidency under the Constitution, but Cruz has muted his criticism of Trump. ("He embodies New York values," Cruz told one radio audience this week.) But is time running so short that Cruz will hit back hard? If he does, will Trump make him regret it?
Will anyone stand out among those jockeying to emerge as an establishment alternative to Trump or Cruz?
Two of the contenders, Florida Sen. Marco Rubio and New Jersey Gov. Chris Christie, have been pounding one another for weeks, a clash that's likely to play out further in the debate. Another, Ohio Gov. John Kasich, has tried to set himself apart as the Republican most willing to take on Trump. A breakout performance in the debate could vault Kasich to the top tier of the race. All three are long shots in Iowa, but a strong showing in New Hampshire could catapult one of them to the nomination.
Can Jeb Bush lift himself out of the campaign's crowded bottom tier?
Despite a giant super PAC war chest, the son and brother of former presidents has sputtered from one poor poll result to another. Lackluster debate performances – including multiple knockdowns by Trump – have only sustained his low standing. Could this one be different?
Can Ben Carson resurrect his candidacy?
Support for the retired neurosurgeon has all but collapsed since the Paris and San Bernardino terrorist attacks shifted the campaign's focus to national security. Much of the novice candidate's backing among evangelicals has shifted to Cruz, a freshman senator whose experience in Congress, however brief, has given him a stronger footing on global affairs. For Carson, who released his foreign policy platform on Tuesday, is it too late to win back those supporters?