John Dean, the former White House counsel to President Richard M. Nixon, slammed President Donald Trump on Wednesday for failing to grasp how impeachment works.

Trump claimed that if the House was to try and impeach him, he would “first head to the U.S. Supreme Court” to block the process.

Dean, dubbed the “master manipulator” of the Watergate scandal before turning on Nixon and cooperating with the investigation, said that’s not how the process works: