The potentially hilarious Donald Trump moderated GOP debate has had few contenders sign up so far, and Jon Stewart made it clear last night why they might be hesitant: Trump "can't ever let anything go." The mogul has a tendency of getting into petty spats (remember his hand scrawled notes to bloggers?) and The Daily Show host zeroed in on the habit with a recent Chuck Todd clip. Donald kept on arguing with Todd about who scheduled the interview. "He can't let go of the question of who called who first, and he's gonna moderate a debate," Stewart quipped. "You think he's going to have any follow up questions?"

Maybe that's why the only two people who were brave enough to enlist so far were frontrunner Newt Gingrich, who seemingly never refuses a debate invite, and nothing-to-lose Rick Santorum. But they should be wary: "If the people in the debate he's moderating don't satisfy him ... he's jumping in" the presidential race himself, Stewart gleefully noted. Or, at least, Trump may feign interest if it will help his just-released book sell.