Republican presidential front-runner Donald Trump and top challenger Ted Cruz ended a longstanding truce in spectacular fashion on Thursday night with bitter exchanges during what may have been Trump's strongest debate performance to date.
The New York billionaire and the Texas senator appeared to have a split decision by the end of the night, a sign that for all the bluster, little took place that could derail Trump from his lead position with a contest in Iowa on Feb. 1 to begin the search for a Republican presidential nominee.
Projections that the debate would be a free-for-all were accurate. Beyond the Trump-Cruz theatrics, U.S. Senator Marco Rubio of Florida turned in a pugnacious performance with attacks on Cruz and New Jersey Governor Chris Christie. Florida Governor Jeb Bush presented himself as a voice of reason against Trump.
A Google snap poll showed viewers believed Trump, who in the most recent debates was at times less engaged, won the night with 37.3 percent to Cruz's 26.6 percent and Rubio's 12.1 percent.
Until the Fox Business Channel debate in North Charleston, South Carolina, Trump and Cruz had been friendly because they have both been chasing conservatives of the Tea Party movement and did not want to anger them.
With Trump now needing to fend off Cruz's rise in Iowa, he pushed his charge that Cruz may not be constitutionally qualified to serve as president because he was born in Canada. The U.S. Constitution says only "natural born" citizens can become president of the United States.
"Who the hell knows if you can even serve in office?" Trump told Cruz, drawing a scattering of boos in the audience.
Born in Calgary, Alberta, to a U.S. citizen mother and a Cuban father, Cruz accused Trump of bringing up his birthplace simply because Cruz was leading some polls in Iowa.