A chilling moment revealed in “I Alone Can Fix It: Donald J. Trump’s Catastrophic Final Year,” the new book about the Trump White House in its waning days by Washington Post reporters Carol D. Leonnig and Philip Rucker, should deeply concern all of us. Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, said he feared a coup was in the making. More specifically, he worried that the U.S. military would be forced to choose sides in an insurrection, something not seen since the Civil War.

Milley went so far as to compare the situation to Adolf Hitler’s rise to power in the 1930s, calling Trump’s supporters “brownshirts in the streets” and fearing what he called a “Reichstag moment.” In a period when others have been called hysterical for making allusions to the Third Reich, this time it was a sober, levelheaded general officer doing so. The comparison is not a perfect one, but the actual history of the military and Hitler’s rise to power is instructive for us today — and should give us some hope that we are not at risk. This history is a story of two key moments — neither of which, in this instance, was the Reichstag fire of Feb. 27, 1933, which solidified Hitler’s power but did not involve the military.

The German military played a critical role both in giving and denying Hitler power. Capitalizing on economic depression and the aftermath of World War I, Hitler first attempted to take power in 1923, following the example of Benito Mussolini. He planned to seize the city of Munich by force, hoping this would galvanize public opinion and sweep him to power in Berlin. Crucially, Hitler counted on military support to give him the strength needed for success. He assumed that, as the Reichswehr — the German army in the Weimar period — was politically conservative and not at all happy with the new liberal Weimar government, it would support him. Perhaps the backing of a famed extremist, Gen. Erich Ludendorff, encouraged this idea (see the retired three-star general Michael Flynn or the military participants in the Jan. 6 insurrection at the U.S. Capitol). Ultimately, however, the military opposed Hitler, eventually opening fire on his men. What Hitler had failed to fully comprehend was that the Reichswehr had become less concerned with liberal government and more interested in maintaining order. It would not condone a lawless coup.

In the second instructive moment, however, the military actively chose to back Hitler; this support culminated in the summer of 1934. A year earlier, before the Reichstag fire, a legitimately elected Hitler courted the senior leadership of the Reichswehr. He promised that the military would be freed of domestic responsibilities and would, in the words of one biographer, “concentrate entirely on its role as a future instrument of war.” At a cabinet meeting on Feb. 8, 1933, Hitler declared that “the next five years must be devoted to the remilitarization of the German people.” He then went on to promise huge budgetary increases, which pleased military leaders as well. Most importantly, perhaps, Hitler promised that the military would have nothing to fear from his brownshirts, the SA — its leader Ernst Röhm had been arguing his organization would replace the professional military. Hitler made good on this promise in bloody fashion by ruthlessly decapitating the SA in the Night of the Long Knives, June 30 to July 2, 1934. A month later, Gen. Walter von Reichenau, senior liaison between the Army and the party, told the troops that “the Reich Chancellor kept his word when he nipped in the bud Rohm’s attempt to incorporate the SA in the Reichswehr. We love him because he has shown himself a true soldier.” By August 1934, German soldiers swore an oath directly to Hitler himself.

What do these two moments from history tell us about our own civil-military relations and Milley’s fears of a coup? I would suggest that from both pragmatic and principled perspectives, we have less to fear from military participation in a coup than from paramilitary groups and civilians. This is not to say that our military is without problems, but there are a number of historical reasons to support optimism.