Indonesian killings of 1965–66

The Indonesian killings of 1965–1966 were an anti-communist purge following a failed coup of the 30 September Movement in Indonesia. The most widely accepted estimates are that more than 500,000 people were killed. The purge was a pivotal event in the transition to the "New Order" and the elimination of the Indonesian Communist Party (PKI) as a political force. The upheavals led to the downfall of President Sukarno and the commencement of Suharto's three-decade presidency.

The failed coup released pent-up communal hatreds which were fanned by the Indonesian Army, which quickly blamed the PKI. Communists were purged from political, social, and military life, and the PKI itself was banned. The massacres began in October 1965, in the weeks following the coup attempt, and reached their peak over the remainder of the year before subsiding in the early months of 1966. They started in the capital, Jakarta, and spread to Central and East Java and, later, Bali. Thousands of local vigilantes and army units killed actual and alleged PKI members. Although killings occurred across Indonesia, the worst were in the PKI strongholds of Central Java, East Java, Bali, and northern Sumatra. It is possible that over one million people were imprisoned at one time or another.

Sukarno's balancing act of "Nasakom" (nationalism, religion and communism) had been unravelled. His most significant pillar of support, the PKI, had been effectively eliminated by the other two pillars—the army and political Islam; and the army was on the way to unchallenged power. In March 1967, Sukarno was stripped of his remaining power by Indonesia's provisional Parliament, and Suharto was named Acting President. In March 1968, Suharto was formally elected president.

The killings are skipped over in most Indonesian history textbooks and have received little introspection by Indonesians. Satisfactory explanations for the scale and frenzy of the violence have challenged scholars from all ideological perspectives. The possibility of a return to similar upheavals is cited as a factor in the "New Order" administration's political conservatism and tight control of the political system. Vigilance against a perceived communist threat remained a hallmark of Suharto's three-decade presidency.

Despite a consensus at the highest levels of the American and British governments that it would be necessary "to liquidate Sukarno," as related in a CIA memorandum from 1962, and the existence of extensive contacts between anti-communist army officers and the US military establishment (including the training of over 1,200 officers, "including senior military figures," by the US military, and also providing weapons and economic assistance ), the CIA denies active involvement in the killings. It was later revealed that the American government provided extensive lists of communists to Indonesian death squads. A top-secret CIA report stated that the massacres "rank as one of the worst mass murders of the 20th century, along with the Soviet purges of the 1930s, the Nazi mass murders during the Second World War, and the Maoist bloodbath of the early 1950s."

Background
Support for Sukarno's presidency under his "Guided Democracy" depended on his forced and unstable "Nasakom" coalition between the military, religious groups, and communists. The rise in influence and increasing militancy of the Communist Party of Indonesia (PKI) and Sukarno's support for it, was a serious concern for Muslims and the military, and tension grew steadily in the early and mid-1960s. The third-largest communist party in the world, the PKI had approximately 300,000 cadres and a full membership of around two million. The party's assertive efforts to speed up land reform frightened those who controlled the land and threatened the social position of Muslim clerics. Sukarno required government employees to study his Nasakom principles as well as Marxist theory. Sukarno had met with Zhou Enlai, Premier of the People's Republic of China. After this meeting he decided to create a militia, called a Fifth Force, which he intended to control personally. He ordered weapons from China to be used to equip this Fifth Force. He declared in a speech that he favoured revolutionary groups whether they were nationalist, religious or communist stating "I am a friend of the Communists, because the Communists are revolutionary people. " Sukarno said at a Non-Aligned summit meeting in Cairo (October 1964) that his current purpose was to drive all of Indonesian politics to the left and thereby to neutralise the "reactionary" elements in the army that could be dangerous for the revolution. Sukarno's international policies increasingly reflected his rhetoric.

Coup attempt
On the evening of 30 September and 1 October 1965, six generals were killed by a group calling themselves the 30 September Movement. With many of Indonesia's top military leaders either dead or missing, Suharto, one of the most senior surviving generals, assumed control of the army after a day of chaos, during which Sukarno refused to commit himself to either side. By 2 October Suharto was firmly in control of the capital and announced that a coup attempt had failed. The military blamed the coup attempt on their arch enemies the PKI.

On 5 October, the day of the dead generals' funeral procession, a military propaganda campaign linking the coup attempt with the PKI began to sweep the country. The new leadership circulated photos of the murdered generals, claiming that the communists, particularly communist women, had tortured and castrated them and gouged out their eyes. Later autopsies showed that these claims were fabricated. Sukarno suggested at a cabinet meeting on 9 October that the event be called Gestok, an abbreviation of Gerakan Satu Oktober – "the October 1 Movement". The army-controlled media ignored him and called the movement Gestapu (a reference to the Gestapo, the Nazi secret police). The campaign convinced both Indonesian and international audiences that the murders were cowardly atrocities committed by the PKI against Indonesian heroes, and that the coup attempt was intended to undermine the Indonesian National Revolution and overthrow President Sukarno. The PKI's denials of involvement had little effect. Pent-up tensions and hatreds that had built up over years were released.

Even though 30 September movement killed only 12 people, Suharto presented it as a nationwide conspiracy to commit mass murder. All the millions of people associated with the PKI, even illiterate peasants in remote villages, were presented as murderers and accomplices of the movement. In early 1966, two Indonesian specialists at Cornell University, Benedict Anderson and Ruth McVey, observed in their Cornell Paper that Suharto's army began the anti-communist campaign well after the 30 September movement had collapsed. Between the moment that the movement ended and the moment that the army's mass arrests began, three weeks had elapsed in which no violence or trace of civil war occurred, even according to the army itself. Sukarno constantly protested the purge, stating that the army was "burning down a house to kill a rat."

Historian John Roosa believes that the individuals behind the 30 September movement were PKI members and had provoked the slaughter by launching an ill-conceived anti-military action, but the US and Indonesian army were waiting for a provocation:

From 1958 to 1965 the United States trained, funded, advised, and supplied the army precisely so that it could turn itself into a state within a state. The army ... gradually made itself the government-in-waiting. In the months before October, the United States and the army wanted an incident like the [30 September] movement to occur. They were busy creating the conditions for it and preparing themselves for dealing with it. Eisenhower and the Dulles brothers – Allen at the head of the CIA and John Foster at the head of the State Department – viewed all nationalist Third World leaders who wished to remain neutral in the Cold War as Communist stooges. In full confidence of their right to handpick the leaders of foreign countries, Eisenhower and the Dulleses repeatedly used CIA covert operations to overthrow such leaders: Mossadegh in Iran in 1954, Arbenz in Guatemala in 1954, and Souvanna Phouma in Laos in 1960. The Dulles brothers viewed Sukarno as yet another irritating character who needed to be removed from the world stage."

Political purge
The army removed top civilian and military leaders it thought sympathetic to the PKI. The parliament and cabinet were purged of Sukarno loyalists. Leading PKI members were immediately arrested, some summarily executed. Army leaders organised demonstrations in Jakarta during which on 8 October, the PKI Jakarta headquarters was burned down. Anti-Communist youth groups were formed, including the army-backed Indonesian Student's Action Front (KAMI), the Indonesian Youth and Students' Action Front (KAPPI), and the Indonesian Graduates Action Front (KASI). In Jakarta and West Java, over 10,000 PKI activists and leaders were arrested, including famed novelist Pramoedya Ananta Toer.

The initial deaths occurred during organised clashes between the army and the PKI including Indonesian armed forces units who were sympathetic to communism and were trying to forcibly resist General Suharto's crackdown. For example, much of the Marine Corps, the Air Force, and the Brigade of Police (Brimob) were infiltrated up to commander level by the PKI. In early October, forces of the Strategic Command (Suharto's Kostrad), and the RPKAD paracommandos led by Colonel Sarwo Edhie Wibowo were sent to Central Java, a region with strong Communist allegiances, while troops of uncertain loyalty were ordered out. At the same time, the Siliwangi Division was deployed to guard Jakarta and West Java, both of which, unlike Central and East Java, remained relatively immune to the mass killings. Early fighting in the Central Java highlands and around Madiun suggested the PKI might be able to establish a rival regime centred on these regions. However, widespread fears of a civil war, between factions supported by the United States and China respectively, quickly evaporated, as the forces sent by Suharto took control. Many rebel commanders chose not to fight as Suharto-deployed forces arrived, although resistance came from some, like General Supardjo, for a few more weeks.

As the Sukarno presidency began to unravel and Suharto began to assert control following the coup attempt, the PKI's upper national leadership was hunted and arrested with some summarily executed. In early October, PKI chairman Dipa Nusantara Aidit had flown to Central Java, where the coup attempt had been supported by leftist officers in Yogyakarta, Salatiga, and Semarang. Fellow senior PKI leader, Njoto, was shot around 6 November, Aidit on 22 November, and First Deputy PKI Chairman M.H. Lukman was killed shortly thereafter.

Killings
The killings started in October 1965 in Jakarta, spread to Central and East Java and later to Bali, and smaller outbreaks occurred in parts of other islands, including Sumatra. The communal tensions and hatreds that had built up were played upon by the Army leadership who characterised Communists as villains, and many Indonesian civilians took part in the killings. The worst massacres were in Central and East Java where PKI support was at its strongest. The situation varied across the country and the role of the Army has never been fully explained. In some areas the Army organised, encouraged, trained, and supplied civilian groups and local militias. In other areas, communal vigilante action preceded the Army, although in most cases killings did not commence before military units had sanctioned violence by instruction or example. It was in the earlier stages of the killings that the army's direct involvement in clashes with the PKI occurred. By the end of October, groups of devout Muslims joined the purge of Communists claiming it was their duty to cleanse Indonesia of atheism.

In some areas, civilian militia knew where to find known Communists and their sympathisers, while in others the Army demanded lists of Communists from village heads. PKI membership was not disguised and most suspects were easily identified within communities. The American Embassy in Jakarta supplied the Indonesian military with lists of up to 5,000 suspected Communists. Although some PKI branches organised resistance and reprisal killings, most went passively to their deaths. Not all victims were PKI members. Often the label "PKI" was used to include anyone to the left of the Indonesian National Party (PNI). In other cases victims were suspected or simply alleged Communists.

The killings were done "face to face", unlike the mechanical methods of killing used by the Nazi Germany or by the Khmer Rouge. The methods of killing included shooting, dismembering alive and beheading with Japanese-style samurai swords. Islamic extremists often paraded severed heads on spikes. Corpses were often thrown into rivers, and at one point officials complained to the Army that the rivers running into the city of Surabaya were clogged with bodies. In areas such as Kediri in East Java, Nahdlatul Ulama youth wing (Ansor) members lined up Communists, cut their throats and disposed of the bodies in rivers. Rows of severed penises were often left behind as a reminder to the rest. The killings left whole sections of villages empty, and the houses of victims or the interned were looted and often handed over to the military.

Local Chinese were killed in some areas, and their properties looted and burned as a result of anti-Chinese racism on the excuse that D.N. Aidit had brought the PKI closer to China. In the predominantly Christian islands of Nusa Tenggara, Christian clergy and teachers suffered at the hands of Muslim youth.

Although there were occasional and isolated flare ups until 1969, the killings largely subsided by March 1966, when either there were no more suspects, or authorities intervened. Solo residents said that exceptionally high flooding in March 1966 of the Solo River, considered mystical by the Javanese, signaled the end of the killings.

Java
In Java, much of the killing was along aliran (cultural stream) loyalties; the Army encouraged santri (more devout and orthodox Muslims) among the Javanese to seek out PKI members among the abangan (less orthodox) Javanese. The killings extended to more than PKI members. In Java, for example, many considered "left PNI" were killed. Others were just suspects or were the victims of grievance settling with little or no political motive. Anti-Communist killings were then instigated with youths, assisted by the Army, hunting down Communists.

Conflict that had broken out in 1963 between the Muslim party Nahdlatul Ulama (NU) and the PKI turned to killing in the second week of October. The Muslim group Muhammadiyah proclaimed in early November 1965 that the extermination of "Gestapu/PKI" constituted Holy War ("Gestapu" being the military's name for the "30 September Movement"), a position that was supported by other Islamic groups in Java and Sumatra. For many youths, killing Communists became a religious duty. Where there had been Communist centres in Central and East Java, Muslim groups portraying themselves as victims of Communist aggression justified the killings by evoking the Madiun Affair of 1948. Roman Catholic students in the Yogyakarta region left their hostels at night to join in the execution of truckloads of arrested Communists.

Although, for most of the country, the killings subsided in the first months of 1966, in parts of East Java the killings went on for years. In Blitar, guerrilla action was maintained by surviving PKI members until they were defeated in 1967 and 1968. The mystic Mbah Suro, and devotees of his Communist-infused traditional mysticism, built an army, but Suro and eighty of his followers were killed in a war of resistance against the Indonesian Army.

Bali
Mirroring the widening of social divisions across Indonesia in the 1950s and early 1960s, the island of Bali saw conflict between supporters of the traditional Balinese caste system, and those rejecting these traditional values, particularly the PKI. Communists were publicly accused of working towards the destruction of the island's culture, religion, and character, and the Balinese, like the Javanese, were urged to destroy the PKI. Government jobs, funds, business advantage and other spoils of office had gone to Communists during the final years of Sukarno's presidency. Disputes over land and tenants' rights led to land seizures and killings, when the PKI promoted "unilateral action". As Indonesia's only Hindu-dominated island, Bali did not have the Islamic forces involved in Java, and it was upper-caste PNI landlords who instigated the elimination of PKI members. High Hindu priests called for sacrifices to satisfy spirits angered by past sacrilege and social disruption. Balinese Hindu leader, Ida Bagus Oka, told Hindus: "There can be no doubt [that] the enemies of our revolution are also the cruelest enemies of religion, and must be eliminated and destroyed down to the roots." Like parts of East Java, Bali experienced a state of near civil war as Communists regrouped.

The balance of power was shifted in favour of anti-Communists in December 1965, when the Army Para-commando Regiment and Brawijaya units arrived in Bali after having carried out killings in Java. Led by Suharto's principal trouble shooter, Sarwo Edhie Wibowo, Javanese military commanders permitted Balinese squads to kill until reined in. In contrast to Central Java where the Army encouraged people to kill the "Gestapu", on Bali eagerness to kill was so great and spontaneous that, having initially provided logistic support, the Army eventually had to step in to prevent chaos. Sukarno's choice of provincial governor for Bali, Sutedja, was recalled from office and accused of preparing a communist uprising, and his relatives were tracked down and killed. A series of killings similar to those in Central and East Java were led by black-shirted PNI youth. For several months, militia death squads went through villages capturing suspects and taking them away. Hundreds of houses belonging to communists and their relatives were burnt down within one week of the reprisal crusade being launched on Bali, with occupants being butchered as they ran from their homes. An early estimate suggested that 50,000 people, including women and children, were killed in this operation alone. The populations of several Balinese villages were halved in the last months of 1965. All the Chinese shops in the towns of Singaraja and Denpasar were destroyed and their owners killed after summary stand-up judgements found them to have financially supported the "Gestapu". Between December 1965 and early 1966, an estimated 80,000 Balinese were killed, roughly five percent of the island's population at the time, and proportionally more than anywhere else in Indonesia.

Sumatra
PKI-organised squatters' movements and campaigns against foreign businesses in Sumatra's plantations provoked quick reprisals against Communists, following the Jakarta coup attempt. In Aceh as many as 40,000 were killed, part of the possibly 200,000 deaths across Sumatra. The regional revolts of the late 1950s complicated events in Sumatra as many former rebels were forced to affiliate themselves with Communist organisations to prove their loyalty to the Indonesian Republic. The quelling of the 1950s revolts and 1965 killings were seen by most Sumatrans as a "Javanese occupation". In Lampung, another factor in the killings seems to have been Javanese immigration.

Kalimantan
In West Kalimantan, approximately eighteen months after the worst of the killings in Java, indigenous pagan Dayaks expelled 45,000 ethnic Chinese from rural areas, killing up to 5,000. The Chinese refused to fight back, since they considered themselves "a guest on other people's land" with the intention of trading only.

Religion
Islam in Java was divided between Abangan, who mixed Islam with other religions like Hinduism and native religious practices, and the Santri, who followed standard orthodox Islam. Many Abangans were supporters of the Communist Party. The impoverished Abangan interests were supported by the PKI Communists.

Abangan Muslim Communists made up most of the people who were slaughtered in the mass killings. Abangans were targeted for attacks by Ansor, the youth group of Nahdlatul Ulama. Abangan PKI members were slaughtered by the Santri with help from the Indonesian Army.

Abangan Muslims were forced by the Indonesian government to convert to Hinduism and Christianity in the aftermath of the slaughter, to dissociate them from Communism.

The Abangan felt pressured into choosing either Hinduism or Christianity in the aftermath of the killings to avoid being classified as atheist communists.

Ethnic factors
Sumatran youths massacred Javanese plantation labourers who made up the membership of the PKI in North Sumatra.

Role of anti-Chinese prejudice
Targeting of ethnic Chinese played an important role in the killings in Sumatra and Kalimantan, which have been called genocides. Charles A. Coppel is sharply critical of this characterisation, in which he sees a western media and academics unwilling to face the consequences of an anti-communist agenda that they endorsed, instead scapegoating Indonesian racism and indulging in extravagant and false claims of hundreds of thousands or millions of Chinese killed. Charles Coppel wrote of the distorted coverage in an article titled: "A genocide that never was: explaining the myth of anti-Chinese massacres in Indonesia, 1965–66". Coppel sees the same bias in coverage of the May 1998 riots, where the Volunteer Team for Humanity noted non-Chinese looters made up the majority of those who were killed. His thesis continues to inspire debate.

Commentators have mistakenly claimed that hundreds of thousands of Chinese Indonesians were killed, but this number is certainly incorrect. The killings targeted members of the Communist Party of Indonesia, and few Chinese Indonesians were members. The best estimate is that around 2,000 Chinese Indonesians were killed (out of a total death toll of 500,000), with documented massacres taking place in Makassar and Medan and on the island of Lombok. Robert Cribb and Charles A. Coppel noted that "relatively few" Chinese were actually killed during the purge while the majority of the dead were Indonesian Communists. The death toll of Chinese was in the thousands while the death toll of non-Chinese Indonesians was in the hundreds of thousands. Balinese and Javanese made up the majority of people who were massacred.

Indigenous, non-Muslim, pagan Dayaks expelled 45,000 ethnic Chinese from rural areas, killing 2,000-5,000. The Chinese refused to fight back, since they considered themselves "a guest on other people's land" with the intention of trading only.

Deaths and imprisonment
Although the general outline of events is known, much is unknown about the killings, and an accurate and verified count of the dead is unlikely to ever be known. There were few Western journalists or academics in Indonesia at the time, the military was one of the few sources of information, travel was difficult and dangerous, and the regime that approved and oversaw the killings remained in power for three decades. The Indonesian media at the time had been undermined by restrictions under "Guided Democracy" and by the "New Order's" takeover in October 1966. With the killings occurring at the height of Western fears over Communism during the Cold War, there was little investigation internationally, which would have risked complicating the West's preference for Suharto and the "New Order" over the PKI and the "Old Order".

In the first 20 years following the killings, 39 serious estimates of the death toll were attempted. Before the killings had finished, the Indonesian army estimated 78,500 had been killed, while the PKI put the figure at 2 million. The Indonesian army later estimated the number killed to be 1 million. In 1966, Benedict Anderson had set the death toll at 200,000. By 1985 he concluded that a total of 500,000 to 1 million people had been killed. Most scholars now agree that at least half a million were killed, thus more than in any other event in Indonesian history. An armed forces security command estimate from December 1976 put the number at between 450,000 and 500,000. A 2012 documentary by Joshua Oppenheimer, The Act of Killing, places the number of deaths between 1 and 3 million people.

Arrests and imprisonment continued for ten years after the purge. A 1977 Amnesty International report suggested "about one million" PKI cadres and others identified or suspected of party involvement were detained. Between 1981 and 1990, the Indonesian Government estimated that there were between 1.6 and 1.8 million former prisoners "at large" in society. It is possible that in the mid 1970s, 100,000 were still imprisoned without trial. It is thought that as many as 1.5 million were imprisoned at one stage or another. Those PKI members not killed or imprisoned went into hiding while others tried to hide their past. Those arrested included leading politicians, artists and writers such as Pramoedya Ananta Toer, and peasants and soldiers. Many did not survive this first period of detention, dying from malnutrition and beatings. As people revealed the names of underground Communists, often under torture, the numbers imprisoned rose from 1966–68. Those released were often placed under house arrest, had to regularly report to the military, or were banned from Government employment, as were their children.

Global reaction
To Western governments, the killings and purges were seen as a victory over Communism at the height of the Cold War. Western governments and much of the West's media preferred Suharto and the "New Order" to the PKI and the increasingly leftist "Old Order". The British ambassador, Andrew Gilchrist, wrote to London: "I never concealed from you my belief that a little shooting in Indonesia would be an essential preliminary to effective change. News of the massacre was carefully controlled by Western intelligence agencies. Journalists, prevented from entering Indonesia, relied on the official statements from Western embassies. The British embassy in Jakarta advised intelligence headquarters in Singapore on how the news should be presented: "Suitable propaganda themes might be: PKI brutality in murdering Generals, ... PKI subverting Indonesia as agents of foreign Communists. ... British participation should be carefully concealed."

A headline in U.S. News & World Report read: "Indonesia: Hope... where there was once none". Australian Prime Minister Harold Holt commented in The New York Times, "With 500,000 to 1 million Communist sympathizers knocked off, I think it is safe to assume a reorientation has taken place." The right-wing oilman H. L. Hunt proclaimed Indonesia the sole bright spot for the United States in the Cold War and called the ouster of Sukarno the “greatest victory for Freedom since the last decisive battle of World War II." Time described the suppression of the PKI as "The West's best news for years in Asia," and praised Suharto's regime as "scrupulously constitutional." "It was a triumph for Western propaganda," Robert Challis, a BBC reporter in the area, later reflected. Many Western media reports repeated the Indonesian army's line by downplaying the army's responsibility for and the rational, organised nature of the mass killing, and emphasised the role of civilians instead, invoking the orientalist stereotype of Indonesians as primitive and violent. A New York Times journalist wrote an article titled "When a Nation Runs Amok" explaining that the killings were hardly surprising since they occurred in "violent Asia, where life is cheap."

In recalling the attitudes of US government officials regarding the killings, State Department intelligence officer Howard Federspiel said that "no one cared, as long as they were Communists, that they were being butchered." Within the United States, Robert F. Kennedy was one of the only prominent individuals to condemn the massacres. In January 1966 he said: "We have spoken out against the inhuman slaughters perpetrated by the Nazis and the Communists. But will we speak out also against the inhuman slaughter in Indonesia, where over 100,000 alleged Communists have not been perpetrators, but victims?"

For the USSR, Andrei Sakharov called the killing a 'tragic event' and described it as 'an extreme case of reaction, racism and militarism', but otherwise the Soviet response was relatively muted. Other Communist states issued strong criticism of the killings. The Chinese government stated they were "heinous and diabolical crimes ... unprecedented in history." One Yugoslav diplomat commented that "even assuming the guilt of the politburo [PKI leadership], which I do not, does this justify genocide? Kill the Central Committee, but do not kill 100,000 people who do not know and had no part in it [the 30 September Plot]." The Suharto government was condemned as a "military fascist regime" by the government of North Korea.

The United Nations avoided commenting on the killings. When Suharto returned Indonesia to the UN, communist Albania was the only member state to protest.

Foreign involvement
According to journalist Kathy Kadane, members of the US government provided targeted names to the Indonesian Army, which several US officials have denied. Mark Aarons argues that declassified intelligence reports indicate that "the CIA actually compiled detailed lists of those it deemed dangerous and supplied them to Suharto's forces who ensured those so named were eliminated in the mass killing operations." Alex Bellamy concurs, noting the Indonesian army used a list containing some 5,000 names of suspected PKI members, which was provided to them by the US embassy in Jakarta, to identify some victims. The State Department volume Foreign Relations of the United States, 1964-1968, which the CIA attempted to suppress in 2001, also acknowledges that the US Embassy provided lists of communist leaders to Indonesians involved in the purges, and notes that the US Ambassador to Indonesia, Marshall Green, stated in a 1966 airgram to Washington that the lists of communists were "apparently being used by Indonesian security authorities who seem to lack even the simplest overt information on PKI leadership."

H. W. Brands wrote in 1989 that the Johnson administration expressly refused to supply weapons for the mass killing of Indonesian communists. However, internal memos from 5 and 6 November 1965 reported an Indonesian request for "communications equipment and small arms to arm Muslim and nationalist youths in Central Java for use against the PKI". On 19 November, the Senior Interdepartmental Group "for the direction and coordination of counter-insurgency activities overseas" approved the provisions the Indonesians requested, which was conveyed a month later.

According to Robert Cribb, there is no evidence that the United States significantly increased the scale of the killings. Conversely, Mark Aarons notes that Ambassador Marshal Green is "long seen as one of the principal officials involved in encouraging the slaughter." Bradley Simpson, Director of the Indonesia/East Timor Documentation Project at the National Security Archive, contends that this was "an army-led and U.S.-backed campaign of extermination" and claims that documents show "the United States was directly involved to the extent that they provided the Indonesian Armed Forces with assistance that they introduced to help facilitate the mass killings," which included the CIA providing small arms from Thailand, and the US government providing monetary assistance and limited amounts of communications equipment, medicine and a range of other items, including shoes and uniforms, to the Indonesian military. In a 2008 program on the killings presented by the Australian Broadcasting Corporation, Bradley Simpson states:

These documents have enabled to gain a much clearer understanding of the precise role of the United States, Britain, Australia and other western governments in both attempting to provoke an armed takeover of Indonesia in 1965 and in supporting the mass killings by the army and civilian groups which followed the September 30 movement. Prior to the last few years scholars have largely speculated on the role of the American Central Intelligence Agency and other western intelligence agencies in pursuing covert operations aimed at provoking an armed conflict between the Indonesian army and the Indonesian communist party or the PKI. But these declassified documents lay out a picture of active engagement with one of the great atrocities of the 20th century, and make the United States and other western governments de facto accomplices in this campaign of mass murder that stretched through the end of 1965 and into 1966.

President Johnson's Security Advisor McGeorge Bundy reported to the president that the events since 1 October had been "a striking vindication of US policy towards Indonesia in recent years: a policy of keeping our hand in the game for the long-term stakes despite recurrent pressure to pull out" and that it was made clear to the Indonesian army that "the Embassy and the US government are generally sympathetic with and admiring of what the army is doing."

The British journalist John Pilger stated that Roland Challis, BBC south-east Asia correspondent at the time, told him how the British government was secretly involved in the slaughter: "British warships escorted a ship full of Indonesian troops down the Malacca Straits so they could take part in the terrible holocaust. I and other correspondents were unaware of this at the time ... There was a deal, you see."

Of all countries, Swedish arms supplies seem to have been the most substantial. According to a report by an Indonesian refugee in Japan, from early December 1965, Indonesia signed "a contract with Sweden for an emergency purchase of $10,000,000 worth of small arms and ammunition to be used for annihilating elements of the PKI." Concerns about the slaughter at the Swedish Embassy did grow some months later, but apparently after the fact.

Documentary filmmaker Joshua Oppenheimer, director of The Act of Killing and The Look of Silence, called on the US to account for its role in the killings during a screening of the former for US congress members. On 10 December 2014, the same day The Act of Killing was released in Indonesia, Senator Tom Udall (D-NM) introduced a "Sense of the Senate Resolution" which condemned the killings and called for the declassification of all documents pertaining to US involvement in the events, noting that "the U.S. provided financial and military assistance during this time and later, according to documents released by the State Department."

Impact
Sukarno's balancing act of "Nasakom" (nationalism, religion, communism) had been unravelled. His most significant pillar of support, the PKI, had been effectively eliminated by the other two pillars—the army and political Islam; and the army was on the way to unchallenged power. Many Muslims were no longer trusting of Sukarno, and by early 1966, Suharto began to openly defy Sukarno, a policy which had previously been avoided by army leaders. Sukarno attempted to cling to power and mitigate the new-found influence of the army, although he could not bring himself to blame the PKI for the coup as demanded by Suharto. On 1 February 1966, Sukarno promoted Suharto to the rank of Lieutenant General. The Supersemar decree of 11 March 1966 transferred much of Sukarno's power over the parliament and army to Suharto, ostensibly allowing Suharto to do whatever was needed to restore order. On 12 March 1967, Sukarno was stripped of his remaining power by Indonesia's provisional Parliament, and Suharto named Acting President. On 21 March 1968, the Provisional People's Representative Assembly formally elected Suharto as president.

Several hundred or thousand Indonesian leftists travelling abroad were unable to return to their homeland. Djawoto, the ambassador to China, refused to be recalled and spent the rest of his life outside of Indonesia. Some of these exiles, writers by trade, continued writing. This Indonesian exile literature was full of hatred for the new government and written simply, for general consumption, but necessarily published internationally.

In December 1965, the US embassy in Jakarta had sent a telegram to Washington stating that without the uprising, "removal of foreign oil companies would have been a certainty." In late 1968, the National Intelligence Estimate for Indonesia reported: "An essential part of the Suharto government's economic program ... has been to welcome foreign capital back to Indonesia. Already about 25 American and European firms have recovered control of mines, estates, and other enterprises nationalized under Sukarno. Liberal legislation has been enacted to attract new private foreign investment. ... There is substantial foreign investment in relatively untapped resources of nickel, copper, bauxite, and timber. The most promising industry ... is oil."

Ralph McGehee, a senior CIA operations officer in the 1960s, states in his memoirs Deadly Deceits (which could only be published after the CIA had censored certain sections): "To conceal its role in the massacre of those innocent people the CIA, in 1968, concocted a false account of what happened (later published by the Agency as a book, Indonesia – 1965: The Coup that Backfired).... At the same time that the Agency wrote the book, it also composed a secret study of what really happened. [One sentence deleted.] The Agency was extremely proud of its successful [one word deleted] and recommended it as a model for future operations [one-half sentence deleted.]

The killings served as a direct precedent for the genocidal invasion and occupation of East Timor. The same generals oversaw the killing in both situations, and encouraged equally brutal methods—with impunity.

Legacy and historiography
The killings was heavily tabooed in Indonesia, and if mentioned is usually called peristiwa enam lima, the incident of '65. Inside and outside Indonesia, public discussion of the killings increased during the 1990s and especially after the fall of Suharto in 1998. Jailed and exiled members of the Sukarno regime, as well as ordinary people, told their stories in increasing numbers. Foreign researchers felt more empowered to publish on the topic, with the end of intimidation by the military regime.

The killings are skipped over in most Indonesian histories, and have received little introspection by Indonesians and comparatively little international attention. Indonesian textbooks typically depict the killings as a "patriotic campaign" that resulted in less than 80,000 deaths. In 2004, the textbooks were briefly changed to include the events, but this new curriculum was abandoned in 2006 following protests from the military and Islamic groups. The textbooks which mentioned the mass killings were subsequently burnt, by order of Indonesia's Attorney General. John Roosa's Pretext for Mass Murder (2006) was initially banned by the Attorney General's Office.

The Indonesian Parliament set up a Truth and Reconciliation Commission to analyse the mass killings, but it was suspended by the Indonesian High Court. An academic conference regarding the killings was held in Singapore in 2009. A hesitant search for mass graves by survivors and family members began after 1998, although little has been found. Over three decades later, great enmity remains in Indonesian society over the events. The film The Year of Living Dangerously, based around events leading up to the killings, internationally released in 1982, was banned in Indonesia until 1999.

Satisfactory explanations for the scale and frenzy of the violence have challenged scholars from all ideological perspectives. One view attributes the communal hatreds behind the killings to the forcing of parliamentary democracy onto Indonesian society, claiming that such changes were culturally unsuitable and unnecessarily disruptive in the post-independence 1950s. A contrasting view is that when Sukarno and the military replaced the democratic process with authoritarianism, competing interests—i.e., the army, political Islam, and Communism—could not be openly debated, rather they were suppressed and could only be expressed through violence. Conflict resolution methods have broken down, and Muslim groups and the military adopted an "us or them attitude", and that when the killings were over, many Indonesians dismissed as something the Communists had deserved. The possibility of a return to similar upheavals is cited as a factor in the "New Order" administration's political conservatism and tight control of the political system. Vigilance against a Communist threat remained a hallmark of Suharto's three-decade presidency.

Films
When Suharto was still in power, a film supporting the New Order's version of events, Pengkhianatan G30S/PKI (Betrayal of Indonesia Communist Party) was broadcast annually on the government television station TVRI every 30 September. This version was the only one allowed in open discourse in the country. After Suharto's removal from power, many people, including those involved, told other versions of the events in various books and films. One, the documentary film The Act of Killing, included interviews with individuals who had participated in the mass killings, and its companion piece The Look of Silence follows one grieving family trying to understand why it happened and exposes how those behind the Indonesian genocide still revel in their crimes 50 years on, including boasting on camera how they dismembered, eviscerated, castrated and beheaded alleged communists.