Retired Supreme Court Justice John Paul Stevens didn’t mince his words while discussing President Trump’s shortcomings when it comes to the judicial system in the U.S.

Suggesting he hopes Trump doesn’t cause “too much damage,” Stevens said he thinks the President doesn’t fully understand the role of the judiciary in the U.S. To Trump, everything is political, Stevens said.

“Well, I think he often speaks about them as Obama judges and other kind of judges, but I think that John Roberts was dead right when he said that there are only one kind of judges and they are all working for the federal government,” the 99-year-old Stevens told CNN’s John Berman on Tuesday.

Stevens made headlines last year when he came out against then-Supreme Court nominee Brett Kavanaugh. At the time he said he didn’t think Kavanaugh would make a good judge, but has since come around to the justice.

“He’s a really good judge,” Stevens said.