*Donald Trump is now officially a certified nitwit.

After he was lit up by President Obama and “Saturday Night Live” head writer Seth Meyers at the White House Correspondents’ Dinner Saturday night, he’s now on the offensive again, first calling Meyers a “stutterer,” and also firing back at late night talk-show host David Letterman for saying his prolonged attacks on Obama have begun to “smack of racism.”

In a letter to the host of CBS’ “Late Show with David Letterman,” Trump wrote:

“I was disappointed to hear the statements you made about me last night on your show that I was a ‘racist.’ In actuality, nothing could be further from the truth and there is nobody who is less of a racist than Donald Trump.” He added, “Based upon your statements, and despite the fact that we have always done so well together, especially in your ratings, I am canceling my May 18th appearance on your show. Additionally, please inform your staff that I will likewise not do the ‘Top Ten’ list that they had been trying to set up.”

Yeah, you tell ’em and show ’em Donald. Dave is gonna be in a world of hurt now that you’ve cancelled on him.