President Donald Trump and first lady Melania Trump visit Arlington National Cemetery for the annual Flags In ceremony ahead of Memorial Day on Thursday in Arlington, Virginia. Credit: Andrew Harnik | AP

The president of the United States wields enormous constitutional power. His power as commander in chief of the armed forces is particularly sweeping. His power to pardon is nearly absolute. And a rogue president is almost unconstrained, except by congressional removal from office or politically through the power of the electorate.

A pardon by President Donald Trump of military personnel who have been convicted of battlefield crimes or are pending general court-martial would be enormously damaging to the values of the U.S. armed forces. He should not take this action.

I am the first to admit that small-unit, direct combat is brutalizing and raw. I’ve had four combat tours and been wounded three times. Exhausted, filthy and scared, young troops struggle to survive and keep their buddies alive. You are trying to destroy enemy fighters with rifles and hand grenades and entrenching tools at close range. You are not trying to make an arrest; your purpose is to kill these people.

Civilians accidentally caught up in the fighting and those suspected to be complicit as nonuniformed combatants can be a terribly complicating factor. It’s hard to explain to our citizens the intensity of violence and sheer lethality of the battlefield.

Amid all this chaos and complexity, however, the armed forces subscribes to the rule of law. Our values as a fighting force demand that we not abuse detainees or prisoners of war under our control. Civilians and their property must be protected. We work very hard to minimize collateral casualties. It’s part of our training and our code of conduct.

Our military culture is based on ferocity in battle tempered by disciplined protection for the helpless. It is enforced by our company-level leadership. Older, experienced noncommissioned officers and trained young officers of character set the example. They clearly tell soldiers what the rules of engagement are for each operation. Where there is a failure of discipline, they take action.

We hold our forces accountable for their actions just as we expect our enemies to do so. If we forgive our forces when they step out of line, we can expect our rivals to do the same. Commanders cannot do their jobs properly if soldiers feel there is no price to be paid for stepping out of line. It is a recipe for a battlefield without any rules at all.

A Trump political pardon of those convicted of murder by a jury of their combat peers would signal to the world that we are no longer a disciplined military force. It would invalidate the principles of the congressionally mandated Uniform Code of Military Justice. It would state to the International Criminal Court that we will not hold our forces accountable and give the court grounds to intervene. It would tell foreign fighters that we accept the murder or maltreatment of our own forces if captured.

The president has publicly endorsed the torture of foreign fighters. He has argued for the deliberate targeting of the families of terrorists. If he pardons U.S. personnel convicted by a military court of the direct murder of unarmed detainees or civilians, he will have taken a step to dishonor our armed forces.

There are better ways to honor the many sacrifices and performance of America’s armed forces and veterans than to exonerate those very few who did not follow the rules.

Barry McCaffrey spent 32 years in the U.S. Army as an infantry officer. This column was originally published by The Washington Post.