The decision of some current and former military leaders to criticize President Trump and his desire to deploy troops to American cities is a blessing, demonstrating there are still powerful institutions resisting the country's slide into authoritarianism. But it's also a curse, revealing just how badly all the civilian institutions have failed.

America thus finds itself in a paradox. Civilian control of the military is foundational to our constitutional democracy. Now, however, the survival of that democracy may require the armed forces to reject — or, at least, push back against — the direction and orders of the nation's highest elected official.

Perhaps the most notable leader to speak up against the president is James Mattis — Trump's former defense secretary and a retired Marine Corps general — who on Wednesday gave a statement to The Atlantic decrying Trump's divisive leadership in the face of nationwide protests over the death of George Floyd. He harshly criticized the use of troops this week to clear a path for Trump's photo op at St. John's Church.

"Never did I dream that troops taking that same oath would be ordered under any circumstance to violate the constitutional rights of their fellow citizens — much less to provide a bizarre photo op for the elected commander-in-chief, with military leadership standing alongside," Mattis wrote.

Mattis isn't the only retired leader to speak out. Admiral Mike Mullen and General Martin Dempsey, both former chairmen of the Joint Chiefs of Staff, are among those to make statements in recent days. James Miller, a former undersecretary of defense, wrote an open letter in The Washington Post resigning from the Defense Science Board.

What is really extraordinary, though, are the comments from current military leaders.

Defense Secretary Mark Esper on Wednesday angered the president by saying troops "should only be used as a matter of last resort and only in the most urgent and dire of situations" to respond to the disorder. (He may be a former defense secretary by the time you read this.) General Mark Milley, the current Joint Chiefs chairman, and the top leaders in the Army, Navy, and Air Force have all spoken out in recent days against racism or to remind their subordinates of the constitutional right to protest.

Americans, Milley said in a memorandum, have a constitutional right to freely speak and assemble. "We in uniform — all branches, all components, and all ranks — remain committed to our national values and principles embedded in the Constitution," he wrote.

In normal times, such statements — against racism, for the Constitution — would seem mild. In the current context, though, they appear to subtweet President Trump and his calls to militarily "dominate" American cities facing unrest.

But what we're seeing isn't entirely unprecedented. In 2006, a number of retired generals pushed back against then-Defense Secretary Donald Rumsfeld's mismanagement of the Iraq War. As The New York Times noted, though, those criticisms raised concerns in the military that "the debate risked politicizing the military and undercutting its professional ethos." Even in retirement, generals and admirals are often cautious about criticizing civilian leaders.

That is because unease about the armed forces' role in American democracy goes back to the founding. "A standing military force, with an overgrown Executive, will not long be safe companions to liberty," James Madison told the Constitutional Convention. "The means of defense against foreign danger have been always the instruments of tyranny at home." The framers of the Constitution built in protections against that tyranny — dividing powers between the president, who is both a civilian and commander-in-chief of the armed forces, and Congress, which has the power to declare war. For good measure, they limited Army appropriations to no more than two years at a time. And their successors passed laws like the Posse Comitatus Act to further restrict the possibility that armed forces would be used to enforce domestic policies.

That doesn't mean the military will never be used on American soil — President George H.W. Bush famously deployed troops to Los Angeles during the Rodney King riots in 1992. But such uses are rare, and done in conjunction with state governments, because the country's leaders have long been wary about being seen as using troops as "instruments of tyranny."

President Trump, on the other hand, possesses little or no sense of democratic restraint. He has been happy to politicize the military, to blur lines meant to keep civilians in control and the armed forces out of politics. His willingness to trash democratic institutions is well-established. It is no surprise that instead of trying to calm this week's unrest — instead of seeing the armed forces as a last resort — he has instead decried the "weakness" of governors and advocated a militant response.

Congress, meanwhile, is not restraining the president's strongman impulses. After this week's photo op at the church, reporters asked Republican senators for a reaction — and mostly got defenses of Trump, or feckless "no comments." The legislative branch has increasingly ceded its war-making authority to the president since World War II; it is now unwilling or unable to halt the president's potential abuse of his military power.

Which leaves America's admirals and generals in a terrible position. The democratic norms of our country require them to carry out the president's orders, so long as they are lawful. But carrying out those orders may badly erode democratic norms. There is no good answer to the problem posed by Trump. The military may be the last hope against a total collapse of our republican form of government — but that may mean the republic is already too far gone to save.

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