Former Vice President Joe Biden appeared on Stephen Colbert’s “The Late Show” Monday night and discussed how President Donald Trump’s time in office might influence future U.S. leaders.

“God willing, [Trump’s presidency] will go down as the single exception in American history,” Biden said. “I really mean that.”

TONIGHT: @JoeBiden talks about the state of affairs in Washington, and whether Trump has changed the American presidency forever. #LSSC pic.twitter.com/LtHH7fr8zP — The Late Show (@colbertlateshow) November 14, 2017

Biden said Trump’s administration has made Americans, regardless of political party affiliation, worry about the stability of the country.

“I just think there’s an attack on the system,” Biden said. “And I think people are worried.”

The former vice president also discussed his new memoir, Promise me, Dad, which focuses on the grief he experienced following the death of his son Beau in 2015. Joseph “Beau” Biden III died at the age of 46 after a two-year battle with brain cancer. He served as Delaware’s attorney general from from 2007 to 2015, and planned to run for governor in 2016.

Check out the full interview in the video below.