A first in a Republican debate this season, Donald Trump and Ted Cruz targeting each other.
FOX News Radio's Jared Halpern was there for it in North Charleston, South Carolina:
From America's Election Headquarters...
A non-aggression pact between front-runners Donald Trump and Senator Ted Cruz is officially over.
(Trump) "The fact is, there's a big overhang. There's a big question mark on your head."
Trump, renewing his concerns for the Canadian-born Cruz's natural born citizen status at the Fox Business debate.
(Cruz) "I've spent my entire life defending the Constitution before the U.S. Supreme Court and I'll tell you I'm not going to be taking legal advice from Donald Trump."
Cruz calling the attacks part of a 'New York value' of Trump...
(Cruz) "Socially liberal, or pro abortion, or pro gay marriage."
Trump answering that by hearkening back to his home city's resiliency after 9/11...
(Trump) "No place on Earth could have handled more beautifully, more humanely than New York."
Cruz and Marco Rubio, both first-term Senators, also took each other on over military spending and tax plans.
In North Charleston, Jared Halpern, FOX News.