"These are creatures that need public recognition and public validation," says Stephen Wayne, a Georgetown University professor of government. "When they get behind something and it doesn't go anywhere, or they're embarrassed by it, it's a political failure. It's an ego failure."
"One of the reasons you rehearse so much is so that you won't have these moments," said Stephen Wayne, a government professor at Georgetown University and author of "Road to the White House." "You've answered these questions 100 times before. So you're not thinking. You just give the answer that you're supposed to give."