WATCH: Michael Moore reveals why tonight is first time he’s ‘frightened for the nation’ under Trump
Michael Moore on MSNBC (screengrab)

Academy Award-winning filmmaker and progressive icon Michael Moore explained why the resignation of Defense Secretary Jim Mattis is a terrifying time for the United States during a Thursday evening appearance on MSNBC's "The Last Word" with guest-host Ali Velshi.

"I was just watching the stuff with Mattis ... I think maybe this is the first time I've actually been frightened for the country -- frightened -- in these almost two years," Moore revealed.

"Basically, everyone on the cabinet who would have voted to remove him under the 25th Amendment eventually, they're gone," he explained. "They're out."

"What you have now with Mattis means Trump is going to put in the person that agrees with him and is going to be his dog," Moore predicted. "He's going to do what he tells him to do."

“Any time you have an autocrat, [who] do they want? Running the military — the person that’s going to do what they tell them to do,” he explained.

"We are now -- with Mattis leaving -- closer to a war," he concluded.