Donald Trump and MSNBC host Lawrence O’Donnell are at it again.

The latest brouhaha started when Trump was asked by CNN’s Ashleigh Banfield this week which cabinet position he would want in a hypothetical Romney administration. On Wednesday’s “The Last Word,” O’Donnell scoffed at the notion that Trump would even be nominated: “Romney knows you’re a buffoon, an unconfirmable joke,” O’Donnell said.

Trump fired back on Twitter yesterday, using his 140 characters (and then some) to excoriate O’Donnell as “a poor man’s Ed Schultz.”

Lawrence O’Donnell will soon have another cancelled show to go along with his three cancelled TV series, “Mister Sterling”, “The Kill Point” and “First Monday” … Without clips of me, his show would be completely dead and he knows it. As I have said many times before @Lawrence is the dumbest man on television. He is only angry because I would never have wasted my time doing his completely irrelevant show.

O’Donnell’s response:

@realDonaldTrump Wrong again. I’ve had more cancelled shows that that.

— Lawrence O’Donnell (@Lawrence) February 9, 2012