Over the holidays, President Trump lashed out at outgoing Defense Secretary Jim Mattis, pointedly rebuking the support for U.S. allies that Mattis, equally pointedly, raised in his Dec. 20 resignation letter. Trump also accelerated Mattis’s planned February departure, forcing him out on Tuesday, and this week claimed he had “essentially” fired his defense secretary.

What to make of this public dust-up?

As Michael A. Robinson previously outlined in Monkey Cage, Trump has routinely broken with civil-military norms by, for instance, treating the military like a political constituency and a punching bag.

But somewhat surprisingly, the policy decision that prompted Mattis’s resignation actually reinforced one civil-military norm: Civilians control the military.

Presidents call the shots

Reportedly, Mattis resigned over the president’s decision to withdraw troops from the counter-Islamic State campaign in Iraq and Syria, after making one last attempt on Dec. 20 to persuade Trump to change his mind before submitting his now-famous resignation letter. In that letter, Mattis did not refer directly to the Syria decision but instead made clear the contrast between his “views on treating allies with respect” and the president’s implied disregard for those same partners. Mattis wrote to Trump, “You have the right to have a Secretary of Defense whose views are better aligned with yours.”

Indeed, agreement between the president and the secretary of defense is a key element of civilian control. The secretary is the president’s immediate subordinate at the top of the Title 10 and National Security Act of 1947 chain of command, conveying the commander in chief’s orders to the military.

Trump has been consistent in his desire to pull out of the post-9/11 wars since well before he took office. Nevertheless, the Pentagon was equally consistent in its efforts to persuade him otherwise. For a time, the generals appeared to succeed, convincing Trump to stay the course in Afghanistan in 2017 despite his reported skepticism.

Civil-military relations scholars debate the degree to which military persuasion of civilian leaders is collaborative or problematic. During his surprise visit to al-Asad air base in Iraq on Dec. 26, Trump seemed to suggest that he had capitulated to his senior military advisers against his better judgment but is reasserting control over military policy:

“One year ago, I gave our generals six more months in Syria. I said, ‘Go ahead. Get them.’ And it turns out it was really a year and a half ago. I said, ‘Go get them. We need six months. Go get them.’ Then they said, ‘Give us another six months.’ I said, ‘Go get them.’ Then they said, ‘Go — can we have one more, like, period of six months?’ I said, ‘Nope. Nope.’ I said, ‘I gave you a lot of six months.’ And now we’re doing it a different way.”

Civilians have the ‘right to be wrong’

Many analysts argue that the civil-military relationship is defined by process, and that the president’s abrupt decision on Syria violated ideals of proper process. But perhaps there was a process. Perhaps the president did as he described — listened to and argued with his military advisers, agreed to do it their way — and, when he did not see the results he wanted on the timeline he identified, chose to pursue a different course.

What is surprising is that this is a president who began his tenure by praising “his generals” and by seeming to cede policymaking and military decisions to a cadre of retired and active-duty general and flag officers. The president who boasted about delegating operational decisions to his generals is overriding military preferences. In other words, the civilian commander in chief chose a different path from his military advisers.

Specialists in U.S. civilian-military relations frequently quote Peter D. Feaver’s injunction that civilian control of the military means civilians “have the right to be wrong.” Because civilians have absolute control over the use of the military as an instrument of policy, their word is final, regardless of logic.

Trump may well be wrong. Critics of the decision to pull back troops cite the ongoing threats posed by the Islamic State, Russia and the Taliban, the damage such moves might do to U.S. credibility, and the risks of abandoning allies and partners. In the Monkey Cage, Asfandyar Mir points out the impact of a troop drawdown in Afghanistan.

Nevertheless, it’s important to remember that assertions of civilian control are a hallmark of healthy civil-military relations. As Phillip Carter wrote for Slate, a burgeoning norm of the Trump era has been the military’s “respectful disobedience” to presidential direction, “a formula for saluting their commander in chief while keeping his worst excesses at bay.” Even some of those outside the administration who worried about the possibility of a “soft coup” found comfort in this perilous dilution of civilian control. As Lindsay P. Cohn has written, reliance on the military to oversee civilians risks weakening democratic control of the armed forces.

The military may still be ‘holding the line’ against Trump

There is a distinct possibility that Trump’s reassertion of control may be a one-off. Although he has shown a persistent desire to pull troops out of Afghanistan and the Middle East, Trump has not demonstrated sustained interest in other operational matters. Respectful disobedience from the Pentagon may persist — and it is worth asking whether the timetable for the Syria withdrawal is orderly or a last-ditch attempt at delay.

Yet Pentagon slow-rolling is not unique to the Trump era. In the 1990s, military leaders worked hard to dissuade civilians from using the military to conduct humanitarian interventions in Somalia and Bosnia. At least since Vietnam, military officers have flirted with the notion that civilians may not have the right to be wrong after all.

Ultimately, as the civilian commander in chief, Trump’s decision on Iraq and Syria was his to make. In that sense, the Mattis episode reinforced, rather than eroded, a civil-military norm.

Alice Hunt Friend is a senior fellow at the Center for Strategic and International Studies and a PhD candidate at American University’s School of International Service. She was the principal director for African Affairs in the Office of the Secretary of Defense from 2012 to 2014. Find her on Twitter @ahfdc.