Ron Paul went hard at Newt Gingrich early in Monday night's debate, showing a feistiness toward Gingrich that he hadn't displayed in the past.

Paul, who served with Gingrich in Congress, went after his tenure as House Speaker "It was chaotic, let me tell you. It was a mess," Paul said.

Paul also corrected Gingrich's statement that he had voluntarily left the speakership rather than being pushed out. A GOP-led coup forced Gingrich from power.

"He didn't not run for Speaker two years later," said Paul. "He didn't have the votes, that was what the problem was."

Paul has mostly fought with Rick Santorum during debates, often going back and forth on foreign policy. But if he piles on with Romney and Santorum, both of whom have gone hard after Gingrich in the past, the night could turn into an everybody versus Newt scrum.