A Democratic Fox News contributor on Monday told a tea party activist that she didn't "know what the fuck" she was talking about on live television after she claimed that a federal government program to help impoverished children didn't work.

The Fox News show Hannity returned from a commercial break during their Monday night panel, but instead of hearing host Sean Hannity speak, viewers were treated to Bob Beckel yelling at tea party activist Jennifer Stefano.

"You say that Head Start is a failure!" Beckel exclaimed. "You don't know what the fuck you're talking about!"

"Failure," Stefano replied.

"I just can't stand right wingers who just keep their mouths running all the time," Beckel explained.

"Whoa!" Hannity interrupted. "We apologize."

"I won't apologize," Beckel grumbled. "I'm not going to apologize. We're not on the air."

"Yeah, we really were," Hannity insisted.

"Why were we on the air?" Beckel wondered. "Why are we not on the air now?"

"We are on the air now," Hannity answered. "This is live television."

"I'm sorry about using that foul word," Beckel said, finally apologizing. "But the intent about it is still there. ... And you should run your show a little better instead of having me get caught like that."

"Typical liberal," Stefano charged. "No personal responsibility."

A 2011 report by the Department of Health and Human Services determined that the Head Start program to provide education, health and nutrition services had a "positive impact" on low-income children since its creation in 1965.

"Head Start has benefits for both 3-year-olds and 4-year-olds in the cognitive, health, and parenting domains, and for 3-year-olds in the social-emotional domain," the report found. " For 3-year-olds, there are few sustained benefits, although access to the program may lead to improved parent-child relationships through 1st grade, a potentially important finding for children’s longer term development."

Watch this video from Fox News' Hannity, broadcast April 16, 2012.