“You can take the dog out of the fight, but you can’t take the fight out of the dog.”

Texas Sen. Kay Bailey Hutchison and Massachusetts Rep. Barney Frank proved the expression true when they went at each other like pit bulls on CNN’s State of the Union program Sunday morning.

Though both lawmakers are leaving Washington at the end of the year following long, decorated careers, they proved that they aren’t willing to go quietly into the night when discussing the FBI’s investigation of CIA Director Gen. David Petraeus and the subsequent scandal that ensued.

Frank and Hutchison joined fellow soon-to-be retirees Arizona Sen. Jon Kyl and Connecticut Sen. Joe Lieberman on the weekly program hosted by CNN correspondent Candy Crowley.

The exchange started with the following statement from Hutchison about the FBI’s probe into Petraeus’s personal emails:

“I’m very worried about this. I’m very worried. Um, and I want to know a whole lot more about what the first e-mails really were and, um, did it really trigger a — an FBI investigation of the CIA director and at a low level? And it wasn’t raised to a higher level? I mean if anybody is investigating the director of the CIA, the president of the United States should know immediately. And I feel like, A., we don’t know enough, and, B., I have great concerns about a lot of the surroundings …”

Frank pressed Hutchison for more specifics, asking if she was implying that the FBI was in fact covering up something else.

Hutchison replied that she simply had “great concerns,” which Frank chalked up to weaseling away from the question.

To get the full impact of the exchange, please watch the video above.