I’m back in El Salvador for the first time in thirty years, and I don’t recognize a thing. There are smooth highways from the airport up to San Salvador, the capital, and even at this late hour, along the stretch of dunes dividing the road from the Pacific Ocean, there are cheerful stands at which customers have parked to buy coconuts and típico foods. But I remember a pitted two-lane road, a merciless sun that picked out every detail on the taut skin of corpses, a hole in the sandy ground, the glaring news that four women from the United States, three of them nuns, had just been unearthed from that shallow pit.

“Is there a monument or a sign marking where the four Americanas were killed during the war?” I ask the driver of the hotel van.

“Yes, up in the university, the UCA, where they died.”

“No, those were the six Jesuit priests, years later, in San Salvador. I mean the nuns, in 1980, here.”

“Oh,” he replies. “I don’t remember.”

That event, the rape and murder of four religious workers on their way from the airport up to the city, was no doubt memorable to people like Robert White, the US ambassador in El Salvador during the last year of the Carter administration. He stood grimly at the funeral the next day, looking like another potential target of a putschist right-wing junta that had gone rogue. Already that year, Óscar Arnulfo Romero, the fearless archbishop of San Salvador, had been assassinated—to loud rejoicing by a ruling class that used to call him “Beezelbub.” Weeks after his murder, orchestrated in the darkest back channels of the regime by the notorious ideologue Roberto D’Aubuisson, the Reagan administration cranked up its military involvement in El Salvador, and dedicated billions of dollars to the junta’s fight against an insurgent coalition of guerrillas—Marxist radicals grouped under the umbrella name of Frente Farabundo Martí para la Liberación Nacional (FMLN).

The twelve-year-long war wo...