GOP race has turned into a battle between...

Sparks fly at GOP debate
Sparks fly at GOP debate   

The latest Republican presidential debate shows that the party's 2016 nomination race has, at least for now, turned into a fierce battle between Ted Cruz and Donald Trump.

No one expected this six months months ago. Then, Republican political strategists were simply waiting for Trump's bombastic reality-show campaign to implode, and for so-called "establishment" candidates to power past Cruz, who had called his own party's leader a liar, on the Senate floor.

Neither has happened. Cruz holds a slight lead over Trump in Iowa barely two weeks before the Feb. 1 caucuses. A win there would boost the Texas senator's attempt to overcome Trump's substantial lead in New Hampshire, which votes eight days later and will shape the contours of decisive primary fights thereafter.

Thursday night's debate on Fox Business Channel in Charleston, South Carolina, underscored the centrality of the Trump vs. Cruz dynamic that Republican veterans — who fear either would fare poorly in a general election — are gradually resigning themselves to.

Trump questioned Cruz's constitutional eligibility to serve as president, given his birth in Canada. Cruz, himself a constitutional lawyer, called it legally clear his mother's American citizen made him, too, a "natural-born citizen." Challenged by Cruz, Trump acknowledged he was raising the matter because of the senator's rising position in the polls.

Cruz, who hopes to seize control of the race in conservative Southern states in primaries after Iowa and New Hampshire, accused Trump of harboring "New York values" — which he defined as socially liberal, pro-abortion and gay marriage, focused on money and the media.

Trump called that "very insulting," and shot back with an emotional reference to how New Yorkers responded to the 9/11 attack on Manhattan. The fact that Cruz felt compelled to applaud at that point suggested that Trump won the exchange.

'Democrats are laughing less about Trump'
'Democrats are laughing less about Trump'   

Their rivals tried to elbow into the fray with middling success. New Jersey Gov.Chris Christie, seeking to portray himself as the toughest Republican leader for a dangerous world, scrapped with Florida Sen. Marco Rubio over ideology and political tactics.

Each man hopes a New Hampshire breakthrough can allow him to consolidate more-moderate mainstream Republicans and take on Trump and Cruz. So do former Florida Gov. Jeb Bush and Ohio Gov. John Kasich. But they, like Christie and Rubio, remained on the fringes of Thursday night's principal battles.

The candidate who struggled the most in the debate was retired neurosurgeon Ben Carson — who once challenged Trump in national polls. Yet Carson has faded amid questions about his command of policy questions and turbulence within his campaign team. In a night dominated by displays of political machismo, Carson's soft-spoken manner left him on the outside looking in.