BANGKOK — It was an anti-Communist blood bath of at least half a million Indonesians. And American officials watched it happen without raising any public objections, at times even applauding the forces behind the killing, according to newly declassified State Department files that show diplomats meticulously documenting the purge in 1965-66.
In one of the documents, released on Tuesday, an American political affairs counselor describes how Indonesian officials dealt with prisons overflowing with suspected members of the Indonesian Communist Party, known by the acronym P.K.I.
“Many provinces appear to be successfully meeting this problem by executing their P.K.I. prisoners, or by killing them before they are captured,” said the cable sent in 1965 from the American Embassy in Jakarta, Indonesia’s capital, to the State Department.
Another cable describes how clerics from an influential Muslim organization in Indonesia advised their flocks that atheist “P.K.I. members are classified as lowest order of infidel, the shedding of whose blood is comparable to killing a chicken.”
The level of detail in the cables helps fill out a picture, outlined by previous declassifications of documents, relating to how an anti-American leader in Indonesia was deposed by the military amid mass extrajudicial executions.
“We knew about these things more generally, but it’s great to have this information in black and white so it’s not just based on oral interviews with victims,” said John Roosa, an associate professor of history at the University of British Columbia in Vancouver and author of a book on the events of 1965. “The U.S. was following what was happening very closely, and if it weren’t for its support, you could argue that the army would never have felt the confidence to take power.”
The Indonesian slaughter took place at a time when Southeast Asia, still emerging from colonialism, was energized by socialist ideology.The United States already had boots on the ground in Vietnam. Indonesia, then led by President Sukarno and home to one of the world’s largest Communist parties, was seen by Washington as the next domino that could fall.When a group of hard-line generals blamed Communist Party operatives for a failed coup attempt in 1965, with China accused as a mastermind, Washington did little to challenge that narrative.
The United States government largely stayed silent as the death toll mounted at the hands of the Indonesian Army, paramilitaries and religious mobs. The extrajudicial killings spread beyond suspected Communists to target ethnic Chinese, students, union members and anyone who might have personal feuds with the hit men. Tens of thousands of others were thrown into tropical gulags.Eventually, President Sukarno, with his anti-American talk and socialist sympathies, was replaced by Suharto, a general who held power for 32 years, instituting a policy he called the New Order to reinvigorate the economy through foreign aid and investment.Another of the newly released cables shows how the American Embassy in Jakarta made clear that any aid from the United States was contingent on Sukarno’s being removed from power. Upon Suharto’s ascension in March 1966, that American aid began to flow.
In some of the cables, American diplomats exulted in the abrupt political transition, even as they noted the rising body count. One file refers to the political changes as a “fantastic switch.”
The Indonesian military, which still wields considerable power today, has tried to blame the orgy of violence on a public furious with the excesses of the Communist Party, absolving itself of direct culpability.
But the cables indicate how members of the American foreign service, at least, held the military directly responsible for some of the deaths. One cable alleges that Suharto gave the orders for certain mass executions.
On Wednesday, Pooja Jhunjhunwala, a State Department spokeswoman, said that the department was aware of the documents and noted that the United States government had declassified other documents related to America’s relations with Indonesia in the 1960s.
“The State Department supports the declassification of any relevant documents from the period which do not pose a national security risk,” she said in a statement.
In 2015, Senator Tom Udall of New Mexico reintroduced a resolution in the Senate calling for Indonesia to face up to its traumatic history. He also held the United States to account for its “military and financial support” there, which included providing lists of possible leftist sympathizers to the Indonesian government and, as one cable released Tuesday showed, pushing to bury foreign news coverage of the killings.
The legacy of the massacre continues to divide Indonesia. For decades, under Suharto’s rule, Indonesians dared not call for justice. Even after he was deposed in 1998, there was little effort to set up an Indonesian form of a truth and reconciliation commission.
But in part after the filmmaker Joshua Oppenheimer released a documentary in 2012 called “The Act of Killing,” chronicling the life of an unrepentant hit man in the purge, members of Indonesian society began to delve into its history.
Joko Widodo, the Indonesian president, has talked about the need to address past human rights violations.
Still, there are limits to how far Indonesia is willing to go. Nursyahbani Katjasungkana, a human rights lawyer, helped convene an international people’s tribunal on the killings at The Hague in 2015. (The court had no real authority beyond an airing of testimony, but it held the Indonesian government responsible for crimes against humanity and accused the United States, Britain and Australia of complicity.)
But in recent months, conservative groups have rekindled anti-Communist sensibilities in Indonesia. Efforts last month to organize screenings of Mr. Oppenheimer’s second documentary, “The Look of Silence,” were restricted by a military directive. A mob gathered around a building where Ms. Katjasungkana and others were believed to be gathering to talk about the violence.
“I just hope these new documents will encourage the Indonesian government to be more open and stop the state denial that the military was involved in these atrocities,” she said. “Hopefully, America will also admit its involvement.”
Jusuf Wanandi is a Chinese-Indonesian who supported Suharto for decades, even if he grew disillusioned with his strongman-like leadership. Unlike many of Suharto’s former acolytes, Mr. Wanandi admits that the events of 1965-66 spiraled out of control.
Yet even he advised patience.
“It is impossible to move forward because emotions are still raw,” Mr. Wanandi said. “We need some more time.”
Gardiner Harris contributed reporting from Washington.
A version of this article appears in print on October 19, 2017, on Page A4 of the New York edition with the headline: U.S. Allowed Blood Bath In Indonesia.