"It is an embarrassment to your party to play that card," Matthews said. "This stuff about getting rid of the work requirement for welfare is dishonest, everyone's pointed out it's dishonest, and you are playing that little ethnic card there. You can play games and giggle about it, but the fact is your side is playing that card. You start talking about work requirements, everyone knows what game you're playing. It's a race card."
Matthews railed Priebus over Romney's recent joke about the birther movement.
"This thing about if your name is Romney," Matthews said. "Yeah you went to prep school and you brag about it. This guy's got an African name, he has to live with it. Look who's going further in their life. Who was born on third base? This absurdity, making fun of the birth certificate issue."
"Of course he's playing the race card," he continued. "Why would he bring [the birth certificate] up?"
"Because he's an awkward joker," co-host Mika Brzezinski responded.
"He misfired badly on the joke," Joe Scarborough said.
Tom Brokaw, seated next to Matthews, called it a demonstration of Romney's "awkward sense of humor."
"I do think in fairness that during the debates there was a lot of stuff aimed at the president that was not refuted by leaders of the party," Brokaw said.
Priebus, who stayed mostly silent during Matthews' rant, eventually responded.
"I'm not going to get into a shouting match with Chris," Priebus said, calling his accusations "garbage."
"We've gotten to a point in politics where any moment of levity is frowned upon by guys like you just so you can push your brand," the RNC chairman said. "You know what, good for you."
Last week on "The Tonight Show," Matthews was far less critical of the GOP campaign, but alluded to Romney's awkwardness.
"He's a little remote, you know?" Matthews said. "He says things like, 'Oh, I just left the aircraft.' What are you, a Conehead? What planet are you from? Nobody talks like that. We earthlings have a certain language. [We say] 'I just got off the plane.'"