Comedian Jon Stewart blasted CNN’s “Crossfire” when he appeared on the show Friday afternoon, criticizing its content and hosts in an unusually serious display for the Comedy Central star.

“What you do is not honest. What you do is partisan hackery,” Stewart said. “You have a responsibility to the public discourse, and you fail miserably.”

Stewart’s purported reason for appearing on the show, which is filmed at GW’s Jack Morton Auditorium, was to promote his new book, “America (The Book): A Citizen’s Guide to Democracy Inaction.” At the onset of Stewart’s attack, members of the audience thought he was merely joking. It soon became apparent that his criticism was serious, though, as he continued to berate hosts Paul Begala and Tucker Carlson during the half-hour program.

“I watch your show every day, and it kills me,” Stewart said. “It’s so painful to watch.”

He also accused “Crossfire” of helping politicians by fueling partisan attacks.

“The thing is, we need your help,” Stewart said. “Right now, you’re helping the politicians and the corporations and we’re left out there to mow our lawns.”

Heather Clapp, the show’s coordinating producer, said a packed audience of 250 people – most of them students, parents and alumni who reserved tickets in advance for Colonials Weekend – attended the live show.

“I think we always have guests on ‘Crossfire’ with strong opinions, and Friday was no exception,” she said.

While declining to address Stewart’s comments, Clapp said “Crossfire” audience members benefit from exposure to diverse political opinions.

“People may disagree with some of the opinions expressed on ‘Crossfire,’ but there’s no question that having a national forum on GW’s campus to express that is a good thing,” she said.

A CNN spokesperson did not reply to calls and e-mails asking for the network’s response to Stewart’s criticism.

During commercial breaks and after the show, Stewart could be seen arguing with the hosts. Once the show ended, Carlson told some audience membersthat Friday’s show was the “most uncomfortable 30 minutes” in television history.

Carlson, the show’s conservative host, seemed nervous as he repeatedly tried to redirect the conversation from criticism of “Crossfire.” He criticized Stewart for being Democratic presidential candidate John Kerry’s “butt boy” and not asking tougher questions when the Massachusetts senator appeared on “The Daily Show.”

“Jon, you’re bumming us out. Tell us, what do you think about the Bill O’Reilly vibrator story,” Carlson said, referring to the sexual harassment suit filed against the Fox News commentator.

“We did promise naked pictures of the Supreme Court justices,” said liberal host Paul Begala in a reference to Stewart’s new book.

Carlson also urged Stewart to stop lecturing and “be funny.”

“I’m not going to be your monkey,” Stewart said before he told Carlson he was wasting an “opportunity” to hold politicians accountable when they appear on “Crossfire.”

The attacks turned more personal toward the end of the interview between Carlson and Stewart.

Carlson said to Stewart on his performance, “I do think you’re more fun on your show,” referring to the Emmy-award winning “The Daily Show” on Comedy Central. Stewart replied, “You’re as big a dick on your show as you are on any show.”

-Jeff Baum contributed to this report.