We received multiple listener questions this week all asking a version of the same fundamental question: In light of President Trump taking power for the second time, what are the limits on his authority to direct the military to do his bidding? And relatedly, when if ever, can a member of the U.S. military lawfully refuse to follow the President’s orders? Presumably this is on people’s minds because President Trump has repeatedly suggested he would use the military for his domestic agenda. For example, his Inauguration Day Executive Order declared a national emergency at the border and seemed to authorize the deployment of troops. He has also said he would use the military to carry out mass deportations and to quell protests. He even refused to rule out using the military to take control of Greenland and the Panama Canal. There are also reports that some migrants deported by the Trump administration are being held at Guantanamo Bay—not by ICE, but by the military.

So these questions are important ones and may, before we know it, become highly relevant. To be clear, some of the law in this area is relatively undeveloped, and that’s because it doesn’t come up that often. Generally speaking, presidents and military officers each understand what the guardrails are, what the limits are, and try not to test those waters too much. But here’s my best understanding of the lay of the land.

As you all know, the President of the United States has another very important title: Commander In Chief. He is allowed, as interpreted by the courts, all the way up to the Supreme Court, a very wide berth in how he uses those powers. But even the Supreme Court has ruled famously and on more than one occasion that the president’s authorities and powers—even in wartime—are not unlimited. A prime example is one that every law student probably remembers well, it’s called Youngstown v. Sawyer, a Supreme Court case that offers important lessons about executive overreach. In 1952, during the Korean War, President Truman faced a looming steel worker strike that threatened to disrupt steel production that was crucial to the war effort. To prevent this, he ordered the Commerce Secretary, Charles Sawyer, to seize and operate the steel mills. Sawyer duly directed the mill operators to continue production under federal oversight, effectively placing private industry under government control, all in the name of the war effort. But years later, the justices ruled that Truman overstepped his authority, emphasizing that, even during wartime, the president could not unilaterally take control of private property without congressional approval.

So where does that leave individual service members? Whether you’re talking about soldiers in the field or generals in the theater of battle, the general rule is service members have a duty to obey lawful orders. But there is also a duty to disobey manifestly unlawful orders—that is, orders that a person of ordinary sense and understanding would know to be unlawful.

The problem is that usually orders don’t fall into black and white categories. They exist in a legal gray area. Some might exceed the President’s executive authority, while others might violate an individual’s constitutional rights. It’s a difficult question, and in some ways, as you’re probably thinking as you’re reading these words, soldiers in the field are often between a rock and a hard place. On the one hand, if you affirmatively disobey an order that is later found to be lawful, you risk being court-martialed. On the other hand, if you obey an order that is later found to be unconstitutional and unlawful, you face criminal exposure.

Ultimately, it is up to the individual service member receiving the order, be it from their immediate superior or the president himself, to make a decision. They can and often do also rely on input from legal advisors and military commanders. But historically, the military has almost always carried out presidential orders even when there were questions about their legality. Challenges usually come after the fact in the form of lawsuits that reach the Supreme Court or through congressional pushback.

But some examples should be fairly easy for service members to figure out. For instance, if a commander or a supervisor orders a service member to shoot someone who was already in custody, restrained with their hands behind their back, that clearly would be an unconstitutional and unlawful order, and it should be disobeyed. On the other hand, consider one of the scenarios that might actually become a reality in the near future. Say Trump orders the military to stop protests against his administration. Normally, the law known as the Posse Comitatus Act bars troops from domestic law enforcement, but there’s an exception: the Insurrection Act. So military service members upon receiving an order would have to ask themselves, well, does this fall under the Insurrection Act? And the first question to answer is, has the President actually invoked the Insurrection Act—which, as I understand it, is a legal precursor to ordering the military to engage in this kind of conduct on domestic soil. Then the question becomes, is it up to the individual service member to make a determination of whether or not the invocation of the Insurrection Act was lawful and constitutional?

It seems to me, whatever we might think about it from the sidelines, it’s a bit too much to ask of individual service members. If the question is, can I as a servicemember take action on domestic soil after the President has invoked the Insurrection Act, the answer most servicemembers would likely arrive at is: I probably do have to engage in that conduct. It would be chaos if every individual service member could on his or her own conscience decide whether or not the invocation of the Insurrection Act will withstand legal scrutiny one day. On the other hand, even if you have been given the order to behave as a soldier might in connection with a protest on domestic soil, there could still be particular orders that are unlawful and should be disobeyed. Remember, Trump’s own defense secretary, the former defense secretary, Mark Esper, disclosed that Trump suggested that protesters who were part of the George Floyd marches maybe should have been shot in the legs by the military. One would hope that an individual service member, even if they believed that the Insurrection Act had been properly invoked and could not be questioned, would disobey a clearly unlawful order like that.

Even these limited examples show it’s a pretty fact-specific inquiry, and it pits two values against each other, both important to the preservation of democracy and the protection of national security. You can’t have individual service members deciding case by case every time they get any order, should they obey it, should they not obey it? The presumption, I think appropriately, is in favor of obeying the orders. But in certain cases, to avoid severe and extreme harm and miscarriages of justice and harm to the reputation of the United States, as we’ve seen with the Abu Ghraib incident and some of the enhanced interrogation techniques that have been used, sometimes that individual judgment has to be brought to bear.

It’s a difficult question and one that fortunately doesn’t come up all that often. In fact, historically, instances of the U.S. military defying presidential orders are rare and typically not based on the orders being considered unlawful. Sometimes there are other reasons for the dispute. In 1948, for example, President Truman lawfully mandated the desegregation of the armed forces and that order faced significant resistance from military leadership opposed to the idea of desegregation. There was an Army secretary by the name of Kenneth Royal, who delayed the implementation of the desegregation order and his refusal to comply led to his forced resignation. Another notable example of insubordination from history occurred during the Korean War. General Douglas MacArthur publicly criticized President Truman’s strategy of limited warfare and advocated for a more aggressive approach against China. His challenge to presidential authority, not with respect to any particular wartime action, but his overall opposition to the President’s strategy, also led to his dismissal in 1951. The bottom line, and what’s at the heart of the issue, is this tension between the duty to obey and the duty to the Constitution. Every service member takes an oath, not to the President, but to “Preserve, protect and defend the Constitution of the United States against all enemies, foreign and domestic.” And we will see—perhaps sooner than we want—that tension put to the test.

Commander in ChiefDonald TrumpExecutive OrdersTrump administrationU.S. Military