The My Lai massacre, which left some 500 Vietnamese civilians dead and led to the court-martial of Lt. William Calley, stands as one of the darkest moments in American military history.
Critics have insisted that the military was reluctant to publicly honor what Thompson did. Shortly after My Lai, he received the Distinguished Flying Cross as his crew mates received Bronze stars, but he looks on that cynically.
"It was only to keep me quiet," he said.
Thompson was 24 when he and his two-man crew were ordered to swoop down over the village of My Lai and draw fire so helicopters behind them could destroy the enemy with machine gun and rocket fire.
But they spotted a young Vietnamese girl, injured and lying on the road. Thompson radioed for help and hovered nearby.
He and his crew watched in horror as an American Army officer approached the girl and shot her dead.
They saw the bodies of Vietnamese children, women and old men piled in an irrigation ditch. Thompson landed and implored American soldiers to help the wounded.
Instead, troops fired into the bodies. Shocked, Thompson searched for an explanation to the soldiers' behavior.
"We wanted to find something that would point the blame to the enemy, but it just didn't work," Thompson said. "It all added up to something we just didn't want to believe."
Then Thompson spotted villagers crowded in a hut -- an old woman with a baby in her arms, and a child clutching her leg.
He told the officer in charge to help him get the villagers out. The officer replied that the only help the villagers would get was a hand grenade, Thompson says.
So Thompson placed his chopper down in front of the advancing Americans and gave his gunner, Lawrence Colburn, a simple, direct order: Train your M-60 on the Gis and fire if they attempt to harm the villagers.
Thompson radioed to two gun ships behind him, and together they airlifted a dozen villagers to safety.
He flew back to the irrigation ditch where his other crew mate, Glenn Andreotta discovered a 2-year-old boy, still clinging to his dead mother, but unharmed. He handed him to Colburn.
The standoff lasted 15 minutes.
Few Americans ever knew of Thompson's deed until David Egan, a professor emeritus at Clemson University, saw a BBC documentary on My Lai 10 years ago in which Thompson was interviewed.
"I thought this was a guy that did something that was brave, honorable and morally correct," Egan says. "...I didn't realize he was a forgotten hero."
Egan wrote more than 100 letters to Congress and high-ranking government officials. The Army finally approved Thompson for the Soldier's Medl on Aug. 22, 1996.
Colburn and Andreotta also will receive Soldier's Medals, though Andreotta's will be awarded posthumously. He died in a helicopter crash three weeks after My Lai. His name is etched in the black stone of the Vietnam memorial, where the award ceremony is to take place.
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