Paul was criticizing so-called "chickenhawks," or politicians who are hawkish about going to war but personally shirked the opportunity to serve in the U.S. military.

"I think people who don't serve when they could and they get three or four or even five deferments have no right to send our kids off to war," said Paul in a clear reference to Gingrich.

Gingrich responded: "I was married with a child."

To which Paul famously shot back: "When I was drafted, I was married and had two kids, and I went."

Paul finished his sentence with pursed lips and a steely gaze. The crowd was silent for a moment. Then, it broke out in applause.