Fifty years ago this month, on March 16, 1968, two companies of US Army troops belonging to the Americal Division entered the My Lai and My Khe hamlets of Son My village, in Quang Ngai province, and killed 504 Vietnamese civilians—overwhelmingly women, children, and old men—in cold blood. The national press and political elites have long learned to treat the massacre as a tragedy that did not reflect official US policy. And ever since the Peers Commission report on My Lai was finally released to the public in November 1974 (the completed report had been transmitted to the Army chief of staff in March 1970), the press and public have believed that the commission, led by Lieut. Gen. William Peers, not only revealed the extent of the massacre but exposed the cover-up, implicating officers all the way up to the commander of the Americal Division, Gen. Samuel Koster.

But what the press and public have never understood is that the Peers Commission was involved in an even bigger cover-up: It exonerated the commander of US forces in Vietnam, Gen. William Westmoreland, from any responsibility for My Lai, despite the fact that the policy Westmoreland conveyed to his subordinates was to treat civilians who remained in long-term Vietnamese Communist, or Viet Cong (VC), base areas like My Lai as enemy combatants.

The reason that Peers covered up the responsibility of Westmoreland for My Lai, moreover—as an aide to Peers on the commission staff told this writer—is that Peers was hoping to get a plum command assignment after completing the investigation, and Westmoreland, who had by then been promoted to Army chief of staff, had enormous influence over the decision to grant that assignment.

The Peers Commission learned from the testimony of squad leaders who were briefed on the mission in the hamlet that day that the company commanders had told them that they were to consider civilians as the enemy. As one squad leader, Sgt. Charles West, recalled, company commander Capt. Ernest Medina told squad leaders that the village “consisted only of North Vietnamese army, Vietcong, and VC families” and “the order was to destroy Mylai and everything in it.” Another squad leader who attended Medina’s briefing also recalled that Medina had told the company that My Lai was a “suspected VC stronghold and that he had orders to kill everybody that was in that village.” A second company commander, Capt. Earl Michles, conveyed the same message to squad leaders.

That testimony led the Peers investigation to the parent unit, the 500-man strike force called Task Force Barker, commanded by Lieut. Col. Frank Barker. The commission concluded, “The orders that were issued through the TF Barker chain of command conveyed an understanding to a significant number of soldiers in C Company that only the enemy remained in the operational area and that the enemy was to be destroyed.”

It would have been an explicit, punishable war crime to state in a directive or in an official briefing to the commanders of Task Force Barker that they were to consider those civilians as no different from combatants and therefore subject to killing. But the Peers Commission concluded that the orders had “conveyed an understanding” of such a policy, allowing the unit commanders to draw the obvious inference about how to treat the civilian population there.

Given that conclusion, the Peers Commission exhibited a remarkable lack of curiosity about whether Barker conveyed this understanding deliberately, and what guidance Westmoreland had provided to commanders as head of the Military Assistance Command Vietnam (MACV). The commission suggested that Westmoreland’s command bore no responsibility whatsoever, describing the policy guidance from MACV on treatment of civilians in glowing terms as “consistent in adhering to the humane standard of protecting the civilians within the combat zone.” It quoted, for example, from Directive 95-4, which ordered pilots to “endeavor to minimize noncombatant casualties and civilian property damage.”

But such quotes were deliberately misleading. They described rules of engagement designed solely for populated areas over which the Viet Cong had held either temporary control or no control at all. My Lai was located in an area where the Vietnamese Communist movement had maintained control and political support for years. Nevertheless, the report did not cite a single official document or section of a document that related to rules of engagement designed specifically for operations targeting villages or hamlets under long-term Communist control.

The Peers Commission cited approvingly MACV Directive 525-3, titled “Combat Operations: Minimizing Non-combatant Casualties,” which was first issued on September 7, 1965, and reissued in a slightly revised form on October 14, 1966.

The commission sought to give the impression that Directive 525-3 had forbidden indiscriminate airstrikes and artillery attacks on populated areas in what were called “specified strike zones”—also known within the US military as “free-fire zones.” It said one of the “significant points” in the directive was that such zones “should be configured to exclude populated areas.” But what Directive 525-3, which this writer obtained from Army historical archives, actually said was, “Specified strike zones should be configured to exclude populated areas except those in accepted VC bases.” [Emphasis added.]

The Peers Commission thus exonerated Westmoreland by suppressing the crucial part of the sentence that showed exactly the opposite of what it was asserting. The directive actually allowed the creation of free-fire zones in hamlets and villages under long-term Viet Cong control such as My Lai, in which the civilian population would have no protection whatsoever. Although the official MACV directive did not explicitly state that civilians living in “specified strike zones” were not to be given any protection, it clearly implied that this was indeed the policy.

That was how officers in areas with free-fire zones interpreted the directive. Only two days after the My Lai massacre, a South Vietnamese government field worker reported from Son My village that 427 people had been killed in My Lai and the other hamlets, including both civilians and guerrillas. Lieut. Col. William Guinn, the deputy province adviser for Quang Ngai province, read a translation of the report. He later testified to the Peers Commission that he had not believed the report, for various reasons, but that, even if it were true, he “didn’t consider it a war crime,” because “these people had been killed by an act of war…because that was a free fire zone out there…”

In 1967, just months before My Lai, Westmoreland addressed the Tiger Force, a commando unit that operated in Quang Ngai province and articulated the logic of US military strategy in that province:

If the people are in relocation camps, they’re green, so they’re safe. We leave them alone. The Vietcong and NVA are red, so we know they’re fair game. But if there are people who are out there—and not in the camps—they’re pink as far as we’re concerned. They’re Communist sympathizers. They were not supposed to be there.

General Peers had a personal incentive to avoid delving too deeply into the question of Westmoreland’s responsibility for what happened at My Lai. At the time he was ordered to undertake the investigation, Peers was a three-star general who was chief of the army’s reserve forces. But it was Westmoreland, by then promoted to Army chief of staff, who had appointed Peers, and Westmoreland remained in that position during the entire Peers Commission investigation. Thus Peers was still subject to Westmoreland in the chain of command. He could not investigate Westmoreland’s responsibility for My Lai without putting his own career in jeopardy.

Westmoreland’s authority to reward or punish was clearly an influence on Peers. Jerome Walsh Jr., who was associate special counsel to the Peers investigation, recalled in a telephone interview with this writer in March 2008 that Peers had confided to him that he hoped to become commander of the Eighth Army in South Korea after the My Lai investigation. In order to get such a top-level command post, Peers would have needed the support of the Army chief of staff.

Another general had already been named commander of the Eighth Army in the autumn of 1969, weeks before the decision to create the Peers Commission. But Peers had been appointed deputy commander of the Eighth Army, a position from which he could reasonably hope to become commander at the time of the next rotation.

But Gen. Creighton Abrams replaced Westmoreland as Army chief of staff in June 1972, before Westmoreland could recommend Peers as new commander of the Eighth Army. And as legal adviser Walsh told this writer, Abrams was extremely hostile to the entire Peers investigation. So in the summer of 1973 Peers was passed over; he then took early retirement from the Army at the age of 59. Peers died in 1984, and Walsh died in 2016, having told the inside story of the Peers cover-up only to this writer.

The widespread myth that responsibility for the My Lai massacre was limited to a relative handful of officers and did not reflect official US policy has survived the half-century since that atrocity was carried out. The tragedy of the investigation’s failure, and the Peers Commission’s cover-up, is that the United States never went through the national soul-searching about the true depths of evil represented by the US war in Vietnam. The historical consequences of that fact have continued to unfold in the endless American wars of the 21st century.