"We all had our stories of whom you'd not get in an elevator with and whom you'd protect your young female interns from," Mitchell told her guests, Bloomberg editor Jeanne Cummings and WaPo political reporter Chris Cillizza.
"Some of those former senators were actually expelled," Mitchell added, a possible reference to Sen. Bob Packwood (R-OR), who resigned in 1995 before he could be expelled for serial sexual misconduct.
The panel was responding to the revelations by Gillibrand in a forthcoming interview with People magazine promoting her new book, in which she details episodes of harassment from male colleagues in Congress.
Among other things, Gillibrand was at different times squeezed on the waist, called "chubby," and told to improve her looks in order to win election. The same day her stories came to light, a reporter for Politico tweeted he didn't believe her, before backing down and apologizing.
Cummings called the senators' conduct "outrageous," but said they were unfortunately nothing new, citing her time covering the Anita Hill hearings in the early 90s, in which Hill revealed incidents of sexual harassment from then-Supreme Court nominee Clarence Thomas.
"We've been there. We know this lesson was supposedly learned 25 years ago. And the very idea that one of them touched her, just totally creeps me out," Cummings said. "I mean, we're [regressing] here. We're not getting better. We're going backwards."
"So women and men and people who are in this country and covered the Senate should not be surprised. They should be angry. This is ridiculous," she added.
The panel went on to discuss other issues around treatment of women in the Senate, such as the lack of accommodations for female members of Congress caring for children or working during pregnancy.
"Just the remarkable insensitivity of the old boys network," Mitchell said. "The oldest white male club in the world is the United States Senate."
Watch the clip below: