This was a decidedly mediocre performance, after being drawn into the weeds with Santorum instead of rising above his opposition. While he forcefully attacked Santorum, Romney wasn’t able to pivot to Obama or demonstrate his “presidential” qualities. Indeed, at times he seemed petty, rebuking moderator John King for interjecting during his final answer with “You get to answer the questions you want, I get to answer the questions I want.”

Paul was unapologetic tonight about his opposition to attacking Iran to stop its nuclear development, but he also scored some of the most pointed shots in the debate on Santorum. The highlight of which was calling Santorum “a fake” to his face, and responding to Santorum’s objections of “I'm real, I'm real, I'm real” with a dismissive “congratulations.”

This was his opportunity to shine, to truly claim the mantle of the front-runner — and he missed the boat. Santorum failed to land a blow on Romney, and was pummeled by the former Massachusetts governor for his endorsement of Arlen Specter and for backing the “bridge to nowhere.” The only way tonight could have been worse for Santorum would be if his opponents were sharper — lucky for him they aren’t.

Asked to define himself in one word, Gingrich brought down the house with "cheerful." He did little to insert himself into the debate or reverse a downward slide, but he had a good line.