“There is a thin line between the military’s tolerance for questionable partisan moves over the past three years and the point where these become intolerable for an apolitical military,” said Douglas E. Lute, a retired three-star Army general who coordinated Afghanistan and Pakistan operations on the National Security Council for Presidents George W. Bush and Barack Obama, and later became the American ambassador to NATO. “Relatively minor episodes have accumulated imperceptibly, but we are now at a point of where real damage is being done.”

Mr. Trump’s walk to a church near the White House on Monday, with Defense Secretary Mark T. Esper and the chairman of the Joint Chiefs of Staff, Gen. Mark A. Milley, in tow, may have been the moment everything shifted, Mr. Lute said.

“As that team walked across Lafayette Park with the president,” after the heavy-handed clearing of a peaceful demonstration, he said, “they crossed that line.”

More:

One general officer, speaking on the condition of anonymity to avoid punishment from his superiors, said on Thursday that he was hoping to make it through another day without having to cite his constitutional obligations to decline an illegal order. He said he would not be surprised if he faced such a dilemma in the coming weeks.

Here is a piece in The Guardian that collects the statements of senior military officers laying down a line in the sand to the Commander in Chief. 

On the other side, a conservative reader, not an official but quite prominent in Republican circles, tells me that he can’t stand Trump, but that this show by military leaders strikes him as “a coup.” Another reader, a decorated veteran, says:

My cynical view of anyone who reaches the highest echelon of the military is that they are politicians who have to fully internalize the ethos of the age to reach and maintain their position. I do understand the worry that using the military to quell civil unrest risks making the military a point of division rather than of unity. That is bad for the military as an institution, and worrisome to those who think in institutional terms. But, I still think that their public statements are dangerous and out of line, unless there are things happening I’m not aware of.

Whichever side you think is right, it really is a staggering thing to think that in the United States of America, military elites (even if out of uniform) are signaling that the authority of the Commander in Chief is uncertain (in the sense that they believe this Commander in Chief cannot be trusted not to abuse it unconstitutionally). This is Third World stuff.