Kevin Lamarque / Reuters

President Donald Trump is reportedly planning to mark Memorial Day by pardoning several American military members accused or convicted of war crimes. If he does so, it would undermine our military-justice system, weaken good order and discipline in the ranks, erode trust with our allies and partners, and sanction the worst inclinations of our adversaries.

During my three decades in the Marine Corps, as an enlisted marine and officer, on active duty and in the Reserves, I received endless training. Some was devised to instill discipline and inculcate high standards of conduct. Other training stressed the importance of ethics and adherence to laws and regulations. Some of the training was scenario-based, to demonstrate that choices weren’t always easy or clear, particularly in combat. We were taught to “choose the hard right over the easy wrong.”

Over the course of my three deployments involving combat and peacekeeping duties, I was fortunate never to have been required to fire my weapon to take a life. I did not have to make a split-second decision to kill another human being. But I was trained to do so—taught not just marksmanship, but also practical decision making and the laws of war. We operated with weapons of war, but we were expected to be judicious in their use.

Everyone serving in the U.S. military, from privates to generals, is expected to adhere to the highest standards of conduct, on the battlefield and off. Some do go astray, in matters both minor and major, but the military-justice system exists to hold them accountable for their actions.

The Uniform Code of Military Justice (UCMJ) dates to 1950 and serves as the foundation for military law. Its stated purpose is “to promote justice, to assist in maintaining good order and discipline in the armed forces [and] to promote efficiency and effectiveness in the military establishment.” Pardoning those who have been accused or convicted of serious crimes would undermine the military-justice system.

Those who serve this country in uniform, who are entrusted to operate and carry weapons and are trained and authorized to use deadly force, must adhere to the highest standards of discipline and conduct, and strictly follow the lawful orders they are given. Those who fail in their duties and responsibilities must be held accountable for their decisions and actions. They are accorded due process through the UCMJ and military-justice system, and held accountable by men and women who also serve in the profession of arms.

In civilian courts, a “jury of your peers” might include accountants, electricians, teachers, factory workers, and the self-employed. In the military system, the jury in a court-martial proceeding is composed of fellow service members, members of the same challenging profession, with similar training and experiences. Those convicted by a military judge, or members of a court-martial panel, have truly been judged by a jury of their peers.

Pardoning military war criminals is a departure from our values, and sanctions the mistreatment of combatants without national accountability.

Those convicted of committing crimes that violate the law of war, who used their weapons to wantonly harm innocents or those under their care—the wounded, the sick, prisoners, or detainees—violated their oaths and the sacred trust placed in them. Pardoning them sends a signal to the entire force as well as to our allies and adversaries that the U.S. military can’t be trusted to live up to its values and obligations. This erosion of trust exposes those who volunteer to serve in our armed forces, today and into the future, to greater risk.

If the governments of those countries in which U.S. service members operate do not believe that our military-justice system will hold accountable those convicted of wrongdoing while on their soil, they will increasingly seek to arrest, imprison, and try those service members in their own courts. That is an outcome we cannot accept, and the commander in chief should not take actions that would cause those governments to consider such steps.

Lieutenant Commander John McCain was shot down over North Vietnam in October 1967. In addition to the broken bones suffered in his ejection from his stricken aircraft, he had his shoulder broken by a rifle butt and his foot bayoneted. During his nearly five and a half years as a prisoner of war, he was beaten, tortured, and given little medical care for his injuries. His treatment at the hands of his captors violated the Geneva Conventions and international law governing humanitarian treatment during war or armed conflict. The torture of McCain as a POW is what happens to Americans when other nations depart from accountability for norms of conduct during armed conflict.

Today McCain lies at rest at the United States Naval Academy. He and the other veterans in cemeteries around the world, who have worn the cloth of our nation and upheld its highest values, should be remembered this Memorial Day—a day for commemorating our fallen heroes and their families. Pardons for those who violated the law and their oaths dishonor those who have kept their honor clean and those who have given their last full measure of devotion.

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