In the conflicted history of Latin America, where political upheaval and state violence reached staggering proportions, the early 1980s in Guatemala stand apart. This was the time when security forces answering to military men unleashed a brutal offensive against left-wing guerrillas and their perceived fellow travelers. Independent investigators later concluded that some 1,700 people from several indigenous groups were killed in the 17-month counterinsurgency between 1981 and 1982—unarmed men, women, and children among them.

Though Guatemala has since made the transition from dictatorship to democracy, the memory of such barbarity is an open wound for this Central American nation of 14.1 million. Now all eyes in the hemisphere are on the supreme court in Guatemala City, where former strongman Gen. José Efraín Rios Montt stands accused of waging what may be the dirtiest chapter of Latin America’s dirty wars, capping a civil war that claimed more than 200,000 lives from 1960 to 1996. “As horrific as it got in the Americas, the killing in Guatemala was just off the charts,” says Michael Shifter, president of the Inter-American Dialogue, a Washington-based policy think tank.

The trial under Chief Justice Jazmín Barrios, which began March 19, is expected to drag on for weeks and maybe months, but already is stirring comment across the globe. Rios Montt, 86, is the first former head of state ever to be tried in his own country for actions committed during his rule. The now stooped, white-haired general and his former military intelligence chief, José Maurício Rodriguez Sanchez, stand accused of genocide and “crimes against humanity,” offenses for which there is no statute of limitations and that are not covered by the blanket amnesty for combatants, signed in 1996.

Guatemalan prosecutors charge that the generalissimo waged a campaign to wipe out the Ixil-Maya and three other indigenous communities thought at the time to be in league with Marxist rebels in the countryside. They built their arguments on the word of witnesses and survivors, who told their harrowing stories to United Nations investigators ten years ago. Many described unspeakable atrocities, including cases of victims who were tortured and burned alive. Observers judge these few months as the worst moment in the 36-year civil war that turned this nation on the tropical Central American isthmus into a killing ground. It still roils the region to this day. The case against Rios Montt is the centerpiece of the recently inaugurated Central American Archives, a vast collection on the years of repression, backed by millions of digitalized documents, images, and depositions, housed in Guatemala City.

In a time of relative peace, stability, and sweeping democratic renewal across the region, such brutal tales seem out of place. But not long ago the Americas were seething with ideologically inflected violence. That the victims of the dirty wars are getting their day in court is especially significant in Guatemala, where the powerful military lobby fought—and many battle-weary citizens agreed—to turn the page on the bloodshed in the name of national healing and reconciliation. The outcome is likely to have ripple effects through a region that only now is coming to terms with one of the darkest periods in recent memory.

There is plenty to reconcile. More than 3,000 people were killed under Chilean general Augusto Pinochet, who toppled a democratically elected government in 1973 and clung to power until 1990. An estimated 30,000 died at the hands of Argentina’s ruling junta from 1976 to 1983, while as many as 69,000 Peruvians were killed by state security forces or terrorist groups between 1980 and 2000.

Latin America is in varied stages of truth-telling about its collective past. Peru is completing work on a Memory Museum to the victims of the 20-year conflict between hardline government troops and Maoist Shining Path terrorists. Each side shares nearly equal blame for the two decades of bloodletting, according to a 2003 report by a high-level fact-finding committee.

In 2010, Chile inaugurated its own Museum of Memory and Human Rights in homage to those who were tortured and “disappeared” under the rule of General Pinochet. A Brazilian truth commission is currently poring over the archives on torture and state-sponsored murders during the 1964-to-1985 dictatorship, though a general-amnesty law in 1979 shields most culprits form criminal prosecution.

Argentina has gone further, and recently began hearing criminal cases against dozens of former leaders of the military junta who during just seven years allegedly killed, kidnapped, tortured, and “disappeared” tens of thousands of dissidents and ordinary citizens believed to be state enemies. These trials are the fruit of a legislative reform that rescinded earlier amnesty laws exempting many dirty warriors from criminal liability.

Driving the reckoning is the redemocratization of Latin America. The armed forces have returned to their barracks. Some of the worst strongmen are retired or behind bars, such as former Peruvian president Alberto Fujimori, now serving a 25-year sentence for human-rights abuses and corruption. Disgraced by the bloody dictatorship and after the disastrous 1982 invasion of the British-controlled Falklands/Malvinas islands, the once untouchable Argentine armed forces are now on the dock. Free, if flawed, elections are the rule across the region. Even popular autocrats—in Venezuela, Bolivia, and Ecuador—must answer to voters increasingly attuned to their civil rights and the rule of law.

“A few years ago this would have been inconceivable. The alignment of political forces in Latin America just wouldn’t have allowed it,” says Shifter of the Inter-American Dialogue. “The truth-seeking and criminal trials are signs of political maturity and stability, with tremendous repercussions for the entire region.”

Not everyone in Latin America is pleased. A group of Rios Montt supporters marched on the Supreme Court Building in Guatemala City this week waving signs declaring “There Was No Genocide” and demanding “Respect and Dignity for the Armed Forces.” But they numbered just two dozen in all and barely disturbed the workday bustle of the national capital.

Among the discontents is the sitting president of Guatemala, retired general Otto Pérez Molina, who helped wage the counterinsurgency in the 1980s and refutes charges of genocide. Tellingly, though, Pérez Molina, who was elected in 2011 and immediately called for a national reconciliation, has done nothing to interfere with the investigations and declined to condemn the trial against his former commander. In a country torn apart by bloodshed and recrimination, that alone speaks volumes.