The second debate of the night started with some fireworks as candidates traded jabs.
At center stage, the GOP frontrunner was the only one of 10 candidates to raise his hands when the Fox News hosts asked if anyone onstage would pledge their support to the eventual nominee of the Republican party and pledge to not run an independent campaign against that person?
"I will not make the pledge at this time," businessman Donald Trump said.
That enraged Sen. Rand Paul, who said Trump was "already hedging his bets because he's used to buying politicians."
"This is what's wrong, I mean this is what's wrong. He buys and sells politicians of all stripes, he's... he's already hedging his bet on the Clintons, okay? So if he doesn't run as a Republican, maybe he supports Clinton, or maybe he runs as an Independent, but I'd say that he's already hedging his bets because he's used to buying politicians," Paul said.
Trump didn't end there. He re-insulted Rosie O'Donnell.
Fox news host Megyn Kelly sharply questioned how Trump has described women in the past, criticizing their bodies and making sexually suggestive statements on his television show.
"You've called women you don't like fat pigs, dogs, slobs and disgusting animals," said Kelly.
"Only Rosie O'Donnell," said Trump.
O'Donnell responded on twitter.