Ever since retired Gen. Jim Mattis resigned as secretary of defense in December 2018, he has been under pressure to speak out more forcefully against President Trump. His withering resignation letter — which made clear that he disagreed with Trump’s mistreatment of allies and obeisance to authoritarians — wasn’t enough. His critics, and there were many, demanded a more sweeping denunciation. Mattis refused to provide it, but he promised: “When the time’s right to speak out about policy or strategy, I’ll speak out.”

Now — with Trump eager to unleash U.S. troops on U.S. cities — the time is right. On Wednesday, Mattis unloaded. If words were bullets, this reprehensible administration would have been vanquished as thoroughly as the Iraqi army divisions that Mattis and his Marines confronted in the spring of 2003.

Mattis singled out “the abuse of executive authority that we witnessed in Lafayette Square” when security personnel gassed peaceful protesters “to provide a bizarre photo op for the elected commander-in-chief, with military leadership standing alongside.” “We must reject any thinking of our cities as a ‘battlespace’ that our uniformed military is called upon to ‘dominate,’” he wrote, referring to a phrase employed by Defense Secretary Mark T. Esper, and “we must reject and hold accountable those in office who would make a mockery of our Constitution.” While his censure of Esper was implied, his excoriation of Trump was explicit: “Donald Trump is the first president in my lifetime who does not try to unite the American people—does not even pretend to try. Instead he tries to divide us.”

Mattis just performed his latest service to a country he has served his whole life. He displayed moral courage in a way that few Republicans — and even fewer Trump appointees — have done.

You know Mattis’s words stung because Trump fired back in a lie-filled rant. Trump claimed to have fired Mattis and even to have bestowed the nickname “Mad Dog” on him. Neither charge is remotely true. The dishonest vituperation merely served to underscore the stark difference between the two men. Mattis is a man of honor, courage, dignity and self-sacrifice; Trump does not even know what those words mean. When Mattis speaks, Trump cowers, because Mattis has moral authority and Trump does not.

Mattis’s eloquent statement carries all the more weight because he does not speak alone. In the past few days, there has been an extraordinary uprising among retired generals and admirals who under normal circumstances would never publicly criticize a sitting president. These retired flag officers, especially the four stars, are conscious that they never really go off duty. Even in retirement they continue to reap the rewards of their service — all those corporate boards and paid speeches — and to maintain close links with their successors. They serve as mentors to today’s general officers and would never want to do anything to embarrass them.

So it means all the more that in rapid succession we have heard denunciations of Trump’s misuse of the military from two former chairmen of the Joint Chiefs of Staff (Adm. Mike Mullen and Gen. Martin Dempsey), a former vice chairman of the Joint Chiefs (Adm. Sandy Winnefeld), a former commander of U.S. Special Operations Command (Gen. Tony Thomas) and a former commander of U.S. forces in Afghanistan (Gen. John Allen). The starkest warning came from Allen, who wrote that “the slide of the United States into illiberalism may well have begun on June 1, 2020,” the day of the assault on Lafayette Square.

Their words pack a punch in the Pentagon and help to explain why Esper suddenly decided that it was not a good idea to deploy troops against the demonstrators — and why Gen. Mark A. Milley, the current chairman of the Joint Chiefs, felt compelled to release a letter reminding the troops that they must “remain committed to our national values and principles embedded in the Constitution.”

Both Esper and Milley shamed themselves by walking with Trump across Lafayette Square, but I do not agree with those who say they should resign. The danger is that they would be replaced by gutless wonders even more willing to do Trump’s awful bidding. Eliot A. Cohen, one of our foremost students of civil-military relations, is right to argue in the Atlantic that Esper and Milley should stay in office and risk dismissal by standing up to the commander in chief.

Esper for the first time did that on Wednesday. He ordered troops that had been assembling near Washington to return to their bases — an order that an angry Trump countermanded. Esper may now lose his job but at least he has found his soul — just as Mattis has now found his voice.

I fear a little less today for our future because I see the retired officers rising up to defend our democracy from the greatest threat that we face: the president of the United States. Let their example inspire those still on active duty.

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