United States military operations in Afghanistan, now in their 15th year, are routinely described as America’s longest war. For overseas combat, that is true. But nothing tops the domestic “war on drugs” that an American president declared more than four decades ago. The casualty rate has been exceedingly high.

Nearly 44,000 Americans a year — 120 a day — now die of drug overdoses. Neither traffic accidents nor gun violence, each claiming 30,000-plus lives a year, causes so much ruination. The annual drug toll is six times the total of American deaths in all wars since Vietnam.

There are obviously many historical aspects to this calamity: the crack cocaine epidemic that once laid siege to urban America, for example, or the spread of H.I.V. infection through shared needles. Retro Report, a series of video documentaries that examine major news stories of the past and their continued impact, trains its lens on a heroin scourge that menaced cities in the late 1960s and early ’70s. It was an era when some soldiers, too, came home from Vietnam with a heroin problem.

Even as that plague was beginning to wane, President Richard M. Nixon announced his war on drugs in 1971, and threw a good deal of federal money into it. Treatment programs were part of this enterprise. But rising crime rates, and fear, soon shaped government policies nationally and locally. Preventing and treating addiction took a back seat to locking up users and their dealers for long stretches. The Sentencing Project, an advocacy group on prison issues, says that from 1980 to 2009, the number of people incarcerated for drug offenses rose to about 500,000 from 40,000. It was lost on no one that these inmates were disproportionately African-Americans.