What are the safeguards, set by the US military, to reduce the risk of committing war crimes?

Question

I am talking here about war crimes committed by individuals or units (i.e., not representing a deliberate government/military policy), such as, e.g., the My Lai Massacre during the Vietnam war. One could argue that such things inevitably happen in war, where one's perception of reality is affected by fear, witnessing murder, losing friends, etc. Shooting of a captured Germany soldier in "Fury" gives a fictional but vivid account of how committing a war crime can seem justified and necessary, with the risk of prosecution seeming too remote to be seriously taken into account (especially as compared to other risks).

Moreover, as My Lai Massacre has shown, the army environment gives fertile ground to such behavior: via attitudes like "shoot first, ask later", difficulty of reporting crimes over the heads of hierarchy, and the secrecy and military hierarchy easing cover-up attempts.

What are the measures put in place by modern militaries to reduce the risk of such events taking place and/or ensuring that they are properly reported and prosecuted? Have there been specific changes implemented in the wake of Vietnam, or similar (though smaller scale) events in Afghanistan or Iraq (see Kandahar massacre, Haditha massacre, as well as United States war crimes)?

Naively, one could imagine observer units, not directly subject to the local chain of command - but I cannot see how one could guarantee their security and thus independence on the very troops/officers that they are supposed to observe and report on.

Answer 1

Check out this article about a war crime in Iraq where a group of US soldiers executed several Iraqi civilians (terrorists?). Note it's from 2015; I don't know if things have changed since.

The army definitely provides training to its soldiers to tell them not to do things like this:

The army takes the high road. It instructs its recruits on their solemn obligation to resist illegal orders, and to report war crimes if they occur. In the field it reminds them repeatedly about the rules of engagement—including that they are not allowed to target civilians, or to rape and pillage, or, for instance, to execute blindfolded suspects who have been lined up beside a canal. Furthermore, it maintains an “open door” policy, under which any soldier of whatever rank can go to his commanding officer to report a violation of any kind.

But this policy is not very effective, because everyone involved has a vested interest that war crimes go uninvestigated. There are no mechanisms to protect people reporting war crimes in the army compared to sexual assault.

Critics later blamed [Cunningham, the witness for the war crime] for not coming forward at once, but the army has no mechanisms in place that would have whisked him away and protected him. For precisely that reason, war crimes are more common than is generally supposed: they are simply too dangerous to report. A related truth is that some number of soldier suicides in combat zones are not suicides at all—they are murders committed to cover up crimes. At the highest level, American military leaders must be aware of the pattern. They could begin to remedy the problem if they chose to—just as they have in the case of sexual assaults within the ranks, where immediate protections are offered to accusers. But war crimes are different. The United States takes a serious hit every time one is reported. It seems that the leadership would rather not know about them than have to deal with every one that takes place. The consequence, however unintentional, is that soldiers who report war crimes are put in harm’s way. Had Cunningham come forward in Baghdad, he would have been exposed to a battlefield where there were a hundred ways to die. Even silent dissent was tricky for him now.

Interpret as you will.