The major facts of the case against Army Maj. Mathew Golsteyn are not in dispute: On or about February 22, 2010, Golsteyn killed an Afghan man whom the decorated soldier believed was a member of the Taliban and a bomb maker connected to the deaths of two U.S. Marines two days earlier. And we know this because Major Golsteyn has said so.

In 2015, after an investigation, then-Secretary of the Army John McHugh stripped Golsteyn of his Silver Star, took away his Special Forces tab and gave him an official reprimand. He has now he has been charged with premeditated murder and accused of killing the alleged Taliban member after he was taken into custody.

Because most Americans do not serve in uniform, and even fewer have served in combat, this case is rich with circumstances most will never encounter.

Because most Americans do not serve in uniform, and even fewer have served in combat, this case is rich with circumstances most will never encounter. For example, why is Golsteyn is being charged with murder when the object of combat being to kill enemy combatants? This feels especially contradictory in the context of a conflict like Afghanistan, where people who appear to be innocent civilians are actually in the business of killing Americans.

Making matters even murkier, President Donald Trump has now weighed in on the matter, promising to review the case and calling Golsteyn a hero on Twitter. Is Trump right? Is Golsteyn a hero being unfairly prosecuted for brutality that is justified in the context of a brutal and unpredictable war?

At the request of many, I will be reviewing the case of a “U.S. Military hero,” Major Matt Golsteyn, who is charged with murder. He could face the death penalty from our own government after he admitted to killing a Terrorist bomb maker while overseas. @PeteHegseth @FoxNews — Donald J. Trump (@realDonaldTrump) December 16, 2018

What’s at stake here is nothing less than the core mission statement of the infantry, which is tasked with maneuvering to “destroy or capture” the enemy ”or to repel his assault by fire, close combat, and counterattack.” There are many examples in history of malfeasance in which a lack of aggression resulted in carnage and failure, and young soldiers are taught from the very beginning of their service that overwhelming force and violence needs to be applied if they are to be successful in killing and capturing the enemy — in fulfilling the mission.

In battle, there is not much ambiguity. There is nothing that focuses your attention more than enemy soldiers who are ardently trying to kill you, and your comrades and being in close combat requires overcoming the most abject of fears in circumstances whose hellishness you will never forget.

But killing the enemy is not the only part of that infantry mission statement — you are also, at times, capturing him. It happens more often than most people think, but from time to time enemy soldiers are taken into custody rather than killed, as was the man Golsteyn is being accused of murdering. Sometimes these captives are badly wounded, incapacitated and can’t fight back. Sometimes they just surrender. But at that point, when they are under your control, you inherit responsibility for them and must treat them humanely. Even though captives are among the best sources of intelligence we can encounter, keeping them alive is labor-intensive, burdensome, inconvenient and even tactically dangerous. But you may not just shoot them because it is easier to deal with them that way or you are worried about what they will do if you release them.

Importantly, this principle remains true even in unconventional wars, when we are confronted with an enemy that is stealthy, wily and concealed among the population whose allegiance we are trying to win. It is not just being stodgy and inflexible to assert that, if nations are to succeed in armed combat over the duration of a campaign, individual soldiers may not make up their own rules.

Trump’s tweet about Major Golsteyn’s situation seems to suggest that he may consider pardoning him. Of course, as the commander-in-chief, he can do that. (Indeed, President Richard Nixon pardoned an officer in 1974 convicted of murder during the Vietnam War — another conflict where the rules of engagement sometimes appeared to blur.) But I would be surprised if many experienced officers would be in favor of such a pardon in this case, since it would both invalidate the rules of engagement established by Trump’s own chain-of-command (all of whom have more experience in combat that he does) and, more significantly, severely weaken the military chain-of-command sworn by oath to support and defend the Constitution.

What’s next? An Article 32 investigation. It is the military equivalent of a grand jury hearing — except that Major Golsteyn can be represented by counsel and can cross-examine witnesses, two rights civilians do not enjoy in all but a few jurisdictions. Personal experience with the Uniform Code of Military Justice says that military people are typically sensitive to the difficult choices that combat soldiers must make in the heat of battle. But they are also sensitive to the logic, strategic importance and societal strength of having rules that govern behavior in the most difficult situations.

There are, of course, disadvantages to being — as the cliché goes — a nation of laws rather than a nation of men. But it is something of an irony that, if we fight wars without adhering to rules we establish, we are subjecting ourselves to the grossest inhumanity of our adversaries and the regrets of our consciences.