Mark Milley, the Chairman of the Joints Chief of Staff, knew that Donald Trump didn’t understand the military’s apolitical reputation.

Last year, Milley offered a public apology after appearing alongside Trump in a highly choreographed photo-op at Lafayette Square.

“I should not have been there,” Milley said in a prerecorded video commencement address to National Defense University in June 2020. “My presence in that moment and in that environment created a perception of the military involved in domestic politics.”

That apology irked Trump, according to “Frankly, We Did Win This Election: The Inside Story of How Trump Lost” by Wall Street Journal Reporter Michael Bender:

“Why did you apologize?” Trump asked [Milley]. “That’s weak.”

“Not where I come from,” Milley said. “It had nothing to do with you. It had to do with me and the uniform and the apolitical tradition of the United States military.”

“I don’t understand that,” Trump said. “It sounds like you’re ashamed of your president.”

“I don’t expect you to understand,” Milley said.

Milley had advanced warning of Trump’s lack of understanding about military culture. Bender also reports that Milley was discouraged from taking the Chairman of the Joints Chief of Staff job by Gen. John Kelly, who served as Trump’s chief of staff. “I would get as far away from this f—— place as I f—— could,” Kelly reportedly told Milley.