Former director of national Intelligence James Clapper has expressed concerns that U.S. institutions are “under assault” by President Trump in the wake of former FBI director James Comey’s dismissal. In comments to CNN on Sunday, Clapper said that while he believes the U.S. faces external threats like Russia, the country’s system of checks and balances is “eroding” from internal forces. Asked whether he was referring to the president, Clapper said, “Exactly.” He also said FBI employees found the firing of their former director to be “very disturbing.” Clapper transitioned out of his post as Trump was inaugurated in January. “It’s very disturbing to me—the negative morale impact that this event has had,” Clapper said on CNN’s State of the Union. “People had issues, I’m sure, with Director Comey’s—some of his decisions. That’s fine. People took issue with decisions I made. That’s part of the deal. But I think, as far as his stature as a leader, his integrity, people are very upset about the way he was treated.” Trump abruptly fired Comey last Tuesday, setting off a firestorm of criticism from Democrats and Republicans alike.