Obama: Iowa, December 13, 2007
“It's the kind of moment that you have in the shower several days later. You say, ‘I should have said that.’” That’s how Juan Williams of NPR described Obama’s great smackdown. But Obama delivered his comment right on the spot, in response to a question from Iowa Democratic debate moderator Carolyn Washburn of the Des Moines Register, who asked him how he could expect to change Washington when so many of his advisers were relics of the Clinton administration. “I want to hear that!” Clinton interrupted, laughing a little overenthusiastically. "Well, Hillary," Obama shot back, mock-serious look on his face, "I’m looking forward to you advising me as well." Andrew Sullivan wrote that it was “[o]ne of those split-second responses in which political authority is passed from one person to another.” William Kristol called it the “defining moment” of the Democratic campaign to that point.

Romney: "A Bushel Basket of Apples and Oranges"
In the eighth GOP debate, with Herman Cain still ascendant and Romney looking to solidify himself in early (read: premature) "inevitable nominee" scenarios, he went after Cain's much-ballyhooed 9-9-9 tax plan. Breaking debate rules, he asked Cain directly if his plan would substitute for existing sales taxes. "No. That's an apple, we are replacing a bunch of oranges. [...] You're going to pay the state sales tax no matter what. [...] That's apples and oranges." Now for Romney's slick smackdown: "And I'm going to be getting a bushel basket that has apples and oranges in it, because I'm going to have to pay both taxes, and the people of Nevada don't want to pay both taxes." [Applause.] Just because it was so deliciously good, we can't resist mentioning a second sassy put-down Romney had in that same debate. When on the topic of border security, Romney turned to Perry and said: "Governor Perry, you say you have got the experience. It's a bit like saying that, you know, the college coach that has lost 40 games in a row has the experience to go to the NFL."