MSNBC panel erupts after former White House ethics chief makes fun of Trump

While calling Donald Trump out on his latest "nonsense," George W. Bush's former White House ethics chief inadvertently told a joke that made an entire MSNBC panel burst into laughter.

"He's accusing Robert Mueller of being a Democrat," ex-White House ethics chief Richard Painter said, adding that "everybody in Washington knew that Robert Mueller was a Republican coming into the Bush administration at the FBI."

Painter added that "the only evidence" Trump has of Mueller's Democratic leanings is that "he played on the same high school hockey team as John Kerry."

"I guess that makes him a Democrat," the former Republican joked, causing his co-panelists to start laughing. "It's just ridiculous."

Watch below, via MSNBC: