Journalist Glenn Greenwald, a staunch defender of NSA leaker Edward Snowden, went after Washington Post columnist Ruth Marcus during CNN’s “The Lead” on Thursday after she claimed that Snowden should be punished as a criminal for leaking classified information.

Discussing the New York Times editorial board endorsement of clemency for Snowden, Marcus said the former NSA contractor should have stayed in the United States to face the justice system if he felt he was justified.

“I think Ruth Marcus’ argument exemplifies everything that’s really horrible about the D.C. media,” Greenwald shot back. “First of all, what she said is just completely factually false. If he had stayed in the United States…he would’ve been barred for making the very argument she said he should’ve made.”

Glenn Greenwald Launches Personal Attack on Washington Post Columnist, Horrible D.C. Media

(CNN)

“People in Washington continuously make excuses for those in power when they break the law,” he added. “Ruth Marcus was one of the leaders in 2008, saying that Bush officials that tortured people shouldn’t be prosecuted, they should be protected. She praised and protected FBI agents in 70s who entered people’s homes without warrants and were criminally prosecuted.”

Greenwald then pressed Marcus to say whether Director of National Intelligence James Clapper should be prosecuted for lying to Congress when he said the NSA wasn’t collecting Americans’ communication data.

Marcus said Clapper “shouldn’t be in office,” but refused to say if she thought he should be prosecuted.

Watch the rest of the tense segment via CNN below:

(H/T: Mediaite)