Three days after a US drone obliterated a car in a Kabul street, General Mark Milley, shrugged off reports of civilian casualties, insisting it was a “righteous strike”. On Friday that word came back to haunt America’s top general when the Pentagon was forced to admit that all 10 dead had been civilians, seven of them children. The drone had hit the wrong white Toyota Corolla. It was, Milley said, a “horrible tragedy of war” and “heart-wrenching”. It was the last act in America’s longest war, as senselessly tragic as much of the 20 years that had gone before. It was also a blow to Milley’s credibility as the chairman of the joint chiefs of staff at a time when he needs it most, at the end of a week of revelations of actions during the Trump administration that appeared to bend and possibly break the rules of how civilian leaders and generals are supposed to interact under US democracy. Milley has already confirmed an account in the book Peril, by the Washington Post’s Bob Woodward and Robert Acosta, that he offered to warn his Chinese counterpart if Donald Trump ordered an attack in the last chaotic weeks of his tenure. He has not denied telling junior officers to consult him if Trump ordered a nuclear launch, an order in conflict with the official chain of command. Republicans have been demanding his resignation, and even those who have defended him for being prepared to step in to possibly save the world from an arguably deranged US leader, voiced unease at the example set by a general undermining the authority of the elected commander-in-chief. “I think he did the right thing given the terrible situation that we put him in, but it sets a terrible precedent,” said Tom Collina, policy director at the Ploughshares Fund, which advocates disarmament and non-proliferation. “We see General Milley doing something that is very disturbing, which is to violate the distinction between civil and military authority,” Collina said “The decision to launch nuclear weapons should be a civilian decision. We decided this back in 1945. The military should not be the decider on nuclear use.” Trump gave Milley the top job in December 2018, long before his predecessor, General Joseph Dunford, was due to retire, and against the recommendation of the defence secretary of the time, James Mattis. By all accounts, it was the Bostonian’s plain-speaking affability that seems to have appealed to the capricious president, along with his combat experience, his bulldog demeanour and their shared concern over wastefulness in Pentagon spending. Trump’s respect for tough-sounding men in uniform and bipartisan enthusiasm for Milley in Congress made him hard to fire, which in turn gave him a measure of influence over the president. But the relationship began to wear thin with the Black Lives Matter protests in the summer of 2020. Milley fiercely resisted Trump’s efforts to put active-duty troops on the streets to suppress the protests and supported changing the names of army bases named after Confederate generals. The pivotal moment came on 1 June when Trump staged a photo op in front of the church across from Lafayette Square, the park in front of the White House that had been cleared of demonstrators by riot police using teargas. Milley was dressed in fatigues that day because he was on the way to visit an FBI operations centre when he was summoned by the president at short notice. “So here’s the dilemma for a senior officer,” said a former Pentagon colleague of Milley’s. “You drive back to the Pentagon, take 45 minutes to change clothes and come back over, right? No, the president calls, you just go.” When Milley followed Trump out of the White House gates along with an entourage of cabinet secretaries and aides, he thought they were on the way to thank National Guard officers for their service. It was only when they neared the church and news photographers appeared that he realised he had been hijacked into appearing in uniform at a political stunt. Ten days later, Milley publicly apologised, much to Trump’s disgust. “I should not have been there,” he said in a commencement address at National Defence University. “As a commissioned uniformed officer, it was a mistake that I have learned from.” “He is funny, smart, irreverent, blunt and all that,” said one of Milley’s friends. “But he’s also sort of an obsessive constitutionalist. He reads a lot of history. He believes in American civics and he understands American civics. He understands the branches of government and who’s got what responsibility for what.” It was the historian and constitutionalist in Milley that became increasingly worried in the aftermath of the November election as it became plain Trump would not accept the result. The general’s greatest fear was that the defeated president, in his desperation, would start a war as a pretext for imposing martial law at home. Milley called it the “Reichstag moment”, according to Peril and an earlier book on the last days of the Trump presidency, I Alone Can Fix It. Milley has confirmed his call to his Chinese opposite number to reassure Beijing that Trump would not mount a surprise attack, saying it was “in order to ensure strategic stability” and “were perfectly within the duties and responsibilities of the chairman”. Subsequent reports have suggested Milley had been authorised by the defence secretary at the time, Mark Esper, to make the call. The nuclear launch issue is legally more problematic for Milley. According to the account in Peril, Milley summoned senior officers from the National Military Command Centre (NMCC), the war room at the Pentagon, and made clear that he had to be consulted in the event that the president gave an order for a nuclear attack. There would be no legal basis for Milley’s order. The chairman of the joint chiefs is an adviser to the president but is not in the chain of command. Under the US system, once the president has given the NMCC his verification codes, he can order the one-star general on duty at the NMCC to unleash America’s nuclear missiles and nobody, not even the defence secretary, can stop him. “Milley’s request to the combatant commands to run any use of nuclear weapons through him, would certainly be seen as a violation of both the statute and the norms associated with the chairmanship,” said Katherine Kuzminski, a senior fellow at the Center for a New American Security. “The quiet part of the analysis,” Kuzminski added, was that such actions would be inappropriate in the case of “any other president”. The Trump case presents an anomaly, but there is no guarantee there will not be more Trumps in the Oval Office in the years to come. Milley has said he will provide a full account of his actions when he appears before Congress later this month. His supporters argue that the extraordinary conditions in Trump’s final weeks demanded flexibility from America’s top man in uniform in order to uphold the constitution and his duty to defend the American people. “This is the tension between the de jure role of the chairman of the joint chiefs and the de facto role,” his former Pentagon colleague said. “The chain of command goes from the president to the combatant command, not through Mark Milley but given his experience, his intellect, his willingness to speak truth to power, well – that’s why they have him in the fucking meetings.”