In combat, lives can be erased in an instant. Military men and women accept that as a given. But what if peril stalks them as civilians, long after the guns have fallen silent? As the years pass, does the nation bear an abiding obligation to them when they find they face death on the installment plan?

These are questions that have long dogged a particular group of Americans, several hundred thousand of them, nearly all men. They were soldiers and sailors who, in the first years after World War II, took part in atmospheric nuclear tests conducted in the Pacific and in Nevada. They were posted within range of exploding bombs — in effect made to be guinea pigs in studies of how combat troops might stand up in a war fought with nuclear arms. Across the decades, many among these “atomic veterans” suffered cancers and other diseases. Try convincing them that their troubles had nothing to do with the radiation they absorbed.

On this Memorial Day, their plight shapes the latest installment of Retro Report, a series of video documentaries examining important news stories of the past and their lasting consequences. This episode was prepared in collaboration with Reveal from the Center for Investigative Reporting, based in Emeryville, Calif., near San Francisco.

One theme of the report echoes across America’s more recent conflicts: What does the government owe its men and women in uniform who fall victim not to enemy fire but rather — or so they are convinced — to decisions made by their own commanders? They include Vietnam War combatants who breathed in defoliants sprayed by American aircraft, and later became gravely ill. More recently, those who served in Afghanistan and the Middle East have had to deal with cancers, respiratory problems and incapacitating fatigue. Many suspect the ailments can be traced to their contact years earlier with “burn pits,” assorted poisons and artillery shells made of depleted uranium.