Newt Gingrich entered the top tier of presidential candidates only just recently. What's it going to take for him to stay there? Kenneth Duberstein, former chief of staff under Ronald Reagan, told the Washington Post that Gingrich can't can't go diva on the public if he wants to be in the race for the long haul.

"Newt has to remain uncommonly disciplined — totally focused, no hissy fits — and continue to be the adult that he has been during the election season so far," he said.

Gingrich agreed. “That’s true,” he said. “Hopefully, I’m going to be more disciplined.”