Early morning on March 16, 1968, helicopters carrying U.S. soldiers flew into a tiny village on the eastern side of South Vietnam, bordering the South China Sea. They’d arrived by a series of hamlets, known as My Lai, expecting to find a booby-trapped stronghold of their enemy, the Viet Cong. Instead, all they saw were noncombatants: women, children, elderly men. Many of them were preparing for breakfast.

The Americans, about 100 soldiers from the Army’s Americal division, proceeded to massacre them. Over the next several hours, the civilians in My Lai (pronounced “Me Lie”) and an adjacent settlement were shot and thrown in ditches. The body count: 504 people from more than 240 families. Some women were raped. Huts and homes were burned. Even the livestock was destroyed.

It was one of the worst American military crimes in history and still pierces the collective conscience of Vietnam War veterans. On Friday, an organization called the Vietnam Peace Commemoration Committee is scheduled to hold a vigil in Lafayette Square across from the White House to acknowledge the American war crimes at My Lai.

Right after the attack, the soldiers — who had been told by their superiors the night before that everyone they’d see would be a Viet Cong guerrilla or sympathizer — kept quiet about what they’d done. For more than a year and a half, the public wouldn’t know about the atrocity. Top military officials initially tried to keep a lid on the killings and commanders even touted the mission to the press as a tactical feat. A United Press International wire service account published in newspapers March 16 reported that U.S. infantrymen “tangled with Communist forces threatening the northern city of Quang Ngai Saturday and U.S. spokesmen reported 128 guerrillas slain in the bitter fighting.” But a few paragraphs later, the article, unwittingly, contained an ominous foreshadowing: “Details of the fighting near Quang Ngai were sketchy.”

Soon, a government whistleblower and a promising journalist would expose the atrocity. In early 1969, Ronald Ridenhour, a veteran from Arizona, wrote a letter to the White House, Pentagon, State Department and numerous members of Congress, revealing his conversations with soldiers who participated or saw the attack. Ridenhour’s letter included details that made the allegations credible and worthy of investigation, including map coordinates of My Lai, witness names and the identities of the perpetrators, according to a congressional probe.

Ridenhour’s letters sparked a military investigation. By early September 1969, First Lt. William Laws Calley Jr., a 26-year-old college dropout from Miami who’d served as a platoon leader in the attack, was charged with the premeditated murder of 109 civilians. But the military only released the fact that Calley had been accused of murdering an unspecified number of people. Without knowing the magnitude of his crimes, the New York Times, for instance, only ran a four-paragraph Associated Press article on his arrest, running it on page 14. The press information officer “declined to give details of the case other than to say that the incident occurred in March, 1968, in Vietnam, and that the charge involves the deaths of more than one civilian,” according to the article.

Shortly after Calley had been charged, Seymour Hersh, a freelance reporter and former news aide to antiwar presidential candidate Eugene McCarthy, learned about My Lai from a lawyer opposed to the war. But he only got vague outlines. He started sniffing around. Eventually, he approached a Pentagon source. As he recalled in a New Yorker piece three years ago, the official slapped his hand against his knee, and said, “That boy Calley didn’t shoot anyone higher than this.”

Now Hersh had what he needed to crack the story wide open. Eventually, he found that tiny Times article noting Calley’s full name and arrest. Then he visited Calley at Fort Benning, Ga., where he was being held. Incredibly, the Army allowed Hersh to read and takes note from Calley’s classified charging sheet — the document that showed Calley had been accused of killing 109 people. Even more incredible was that when Hersh completed his exposé and took it to Life and Look magazines, the editors rejected him. So Hersh took his story to the Dispatch News Service, which he described to the New Yorker as “a small antiwar news agency” in Washington. The story broke on the wires Nov. 12, 1969, and appeared in newspapers the next day.

With a dateline from Fort Benning, Ga., Hersh began his story this way:

Lt. William L. Calley Jr., 26 years old, is a mild-mannered, boyish-looking Vietnam combat veteran with the nickname “Rusty.” The Army is completing an investigation of charges that he deliberately murdered at least 109 Vietnamese civilians in a search-and-destroy mission in March 1968 in a Viet Cong stronghold known as “Pinkville.”

Calley told Hersh he was merely following orders. His attorney, George W. Latimer, a former judge on the U.S. Court of Military Appeals, ridiculed the accusations against his client. “This is one case that should never have been brought,” Latimer said. “Whatever killing there was in a firefight in connection with the operation. You can’t afford to guess whether a civilian is a Viet Cong or not. Either they shoot you or you shoot them.”

Deep into the scoop, Hersh, who would win a Pulitzer Prize, wrote that Calley, only 5-foot-3, “seems slightly bewildered and hurt by the charges against him. He says he wants nothing more than to be cleared and return to the Army.” He also told Hersh: “I know this sounds funny, but I like the Army … and I don’t want to do anything to hurt it.”

Hersh’s article prompted front page stories in The Washington Post and the New York Times, and contributed to the swelling anger against President Nixon, who was less than a year into his first term and had earlier that month pleaded for nationwide solidarity to support the war in his famous “Silent Majority” speech. Coincidentally, two days after the publication of Hersh’s story, at least a quarter of a million people gathered by the Washington Monument to demand an end to the Vietnam War. “It surpassed in size the civil rights March on Washington in 1964 and was easily the largest — and was perhaps the youngest — antiwar crowd ever assembled in the United States,” The Post noted.

The massacre at My Lai, meanwhile, continued to make news. In early 1970, charges of trying to cover up the slaughter were brought against Major General Samuel W. Koster, who’d served as the commanding general over the My Lai troops but was now the superintendent at the United States Military Academy at West Point. The news shocked the country. Numerous other officers were charged with concealing the killings, but the accusations against them — and Koster — were eventually dismissed. One brigade commander stood trial on coverup allegations, but was acquitted.

Calley was the only officer convicted of playing a direct role in the massacre. According to Hersh’s account, eleven other men were charged with murder, maiming or assault with the intent to commit murder, but their cases either fizzled out before trial or they were acquitted.

During his trial in early 1971, Calley argued that he was merely following orders — echoing the same lines of the Nazis during the Nuremberg trials. But an Army jury of six men, five of whom served in combat, rejected that defense. On March 29, 1971, Calley was found guilty of the premeditated murder of at least 22 Vietnamese civilians. He was sentenced to life in prison, but Nixon intervened and ordered that he serve under house arrest in a reduced sentence.

But Hersh was not done chronicling these crimes. In early 1972, Hersh compiled all of his research and wrote a mammoth two-part series for the New Yorker on the military’s investigation into My Lai. One soldier, Terry Reid of Milwaukee, described to Hersh what he’d seen when the onslaught erupted.

As soon as they started opening up, it hit me that it was insanity. I walked to the rear. Pandemonium broke loose. It sounded insane — machine guns, grenades. One of the guys walked back, and I remember him saying, “We got sixty women, kids, and some old men.”

Hersh also reported that more than 40 soldiers who spoke to him or government investigators recalled hearing, in advance of the operation, “a specific order to kill civilians.” He quoted one soldier, Larry G. Holmes, who said: “We had three hamlets that we had to search and destroy. They told us they . . . had dropped leaflets and stuff and everybody was supposed to be gone. Nobody was supposed to be there. If anybody is there, shoot them.”

Calley was not done with My Lai, either. He kept appealing his conviction and ultimately took his case into the civilian court system. By November 1974, three months after Nixon resigned, a federal-district court judge ordered Calley’s release, having ruled earlier that the enormous publicity surrounding his case prevented a fair trial. Finally freed, Calley went on to work for his father-in-law’s jewelry store in Columbus, Ga., and, according to Hersh, spent the following years, “offering self-serving interviews to journalists willing to pay for them.”

In August 2009, at a local Kiwanis club near the military base in Georgia where he’d been court-martialed, Calley finally delivered his first public apology. A Columbus Ledger-Enquirer reporter chronicled the dramatic moment.

“There is not a day that goes by that I do not feel remorse for what happened that day in My Lai,” Calley told the Kiwanis members. “I feel remorse for the Vietnamese who were killed, for their families, for the American soldiers involved and their families. I am very sorry.”

But, during a short question-and-answer session, he also couldn’t resist rationalizing what he’d done, either.

“If you are asking why I did not stand up to them when I was given the orders,” Calley said, “I will have to say that I was a second lieutenant getting orders from my commander and I followed them — foolishly, I guess.”

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