Late-night host Stephen Colbert sparred with former White House press secretary Karine Jean-Pierre on Monday over former President Joe Biden's mental acuity and the accusation that the former president was betrayed.

"It was very personal for those of us who watched it too, because it was a shock to our system to see that. Because — I mean, you’re talking to a guy who helped raise $25 million for Joe Biden in March of that same year," Colbert, a staunch Biden supporter, told Jean-Pierre. "And three months later, I saw a guy who I had not seen backstage at the benefit that I did. It seemed like a dramatically different person. And at 81 years old, that’s not entirely unexpected. You can imagine why people got so worried."

Jean-Pierre insisted she had seen Biden every day and argued he was able to govern. The former press secretary has expressed frustration with the Democratic Party for pressuring the former president out of the race, and wrote in her new book, "Independent," that she couldn't "stomach" being part of it anymore.

"I’m not questioning his heart or his policies, but it takes more than that to be the president of the United States," Colbert said. "And in a moment of great pressure on stage, we saw someone shock us and worry us. And nothing could assuage that worry. So I don’t think it was necessarily a betrayal of Joe Biden as other people saying, ‘We don’t think we were shown the Joe Biden that you saw.'"