Anti-communists, initially following the army's lead, went on a violent purge of communists throughout the country, which killed an estimated half a million people and led to the banning and dissolution of the PKI, which was officially blamed for the attempted coup and crisis.

After an internal national revolution and struggle against the former Dutch colonial government, Sukarno had managed to hold together the diverse country; however, his administration had not been able to provide a viable economic system to lift its citizens out of severe poverty.

By the mid-1960s, the cash-strapped government had to scrap critical public sector subsidies, estimates put annual inflation at 500–1,000%, export revenues were shrinking, infrastructure crumbling, and factories were operating at minimal capacity with negligible investment.

Severe poverty and hunger were widespread, and Sukarno led his country in a military confrontation with Malaysia while stepping up revolutionary and anti-western rhetoric.

[4] Described as the great dhalang ("puppet master"), President Sukarno's position came to depend on balancing the opposing and increasingly hostile forces of the army and the PKI.

When Sukarno rejected food aid from United States Agency for International Development, thereby exacerbating famine conditions, the right wing of the military adopted a regional command structure through which it could smuggle staple commodities to win the loyalty of the rural population.

The Confrontation further encouraged the West to seek ways to topple Sukarno, who was viewed as a growing threat to Southeast Asian regional stability (as with North Vietnam under the domino theory).

On the night of 30 September – 1 October 1965, six senior army generals were kidnapped and executed in Jakarta by a battalion of soldiers from the Tjakrabirawa Regiment (Presidential Guard) in an "attempted coup".

The right faction among the top generals was wiped out, including the powerful Chief of Staff of the Army, Ahmad Yani, but the Minister of Defence, Abdul Haris Nasution, escaped.

[7] Calling themselves the "30 September Movement", the group announced on radio around 7 am that they were trying to stop a military coup backed by the US Central Intelligence Agency (CIA) that was planned to remove Sukarno from power.

RPKAD forces proceeded to attack Halim Perdanakusumah AF Base on the morning of 2 October but was stopped by the rebel soldiers in a fierce gunbattle in which several fatalities were inflicted on both sides.

A direct order from President Sukarno managed to secure the surrender of the rebel soldiers by noon, after which Suhartoist forces occupied the base.

[13] After the assassinations of those generals, the highest-ranking officer in the Indonesian military, and third-highest in the overall chain-of-command, was the Defense Minister and Armed Forces Chief-of-Staff Gen. Abdul Haris Nasution, a member of the right-wing camp.

The Army, acting on orders by Suharto and supervised by Minister of Defense Nasution, began a campaign of agitation and incitement to violence among Indonesian civilians aimed at the Communist community and toward President Sukarno himself.

However, the ban was soon used as a pretext for the Indonesian Army to go throughout the country carrying out extrajudicial punishments, including mass arrest and summary executions, against Sukarno loyalists and suspected leftists linked to the PKI and its allied organizations.

More provocatively still, Sukarno fired General Nasution as Minister of Defense and was replaced by MG Sarbini, while Suharto remained as Chief of Staff of the Army and a member of the cabinet.

They daubed slogans, one accusing Subandrio of murdering the generals and drew graffiti showing him as a Pekingese dog (a reference to his perceived closeness to communist China) or hanging from gallows.

Sukarno left the palace in haste for Bogor, where later that night, he signed the Supersemar document transferring authority to restore order to Major General Suharto.

[19][28] On 24 April 1966, Suharto gave a speech to members of the Indonesian National Party in which he spoke of the "three deviations" that would have to be corrected by the youth of the country in co-operation with the Armed Forces.

The now disbanded Tjakrabirawa Regiment was replaced by an Army military police regiment, and following further student demonstrations in front of the legislature building on 2 May, the leadership of the Mutual Cooperation People's Representative Council (DPR-GR) led by Speaker I Gusti Gde Subamia was replaced and Sukarnoist and pro-communist members were stripped of their MP titles from the DPR-GR and the Provisional People's Consultative Assembly (MPRS), the supreme lawmaking body and expelled.

It also ratified the banning of the PKI and the teaching of Marxist ideology, instructed Suharto to form a new cabinet, called on Sukarno to explain the economic and political situation in the nation and stripped him of the title "president for life".

[19][27] Suharto did not seek Sukarno's outright removal at this MPRS session due to the remaining support for the president amongst elements of the armed forces (particularly the Marines, the navy, and some regional army divisions).

It released political prisoners and paid compensation to the British and American governments for the damage caused to their diplomatic buildings during the demonstrations of the Sukarno era.

[27] General Nasution was believed to have launched his own bid for power on 16 December 1965, when he won appointment to the Supreme Operations Command and gained a grip over the traditionally civilian-held portion of the military hierarchy.

While resentment toward Chinese Indonesians by indigenous Indonesians-descended peoples of the archipelago dated back to the Dutch East Indies era, the New Order instigated anti-Chinese legislation following the quashing of the Communists.

Along with the subsequent efforts by Suharto to wrest power from Sukarno by purging loyalists from the parliament, the civilian government in Indonesia was effectively put to an end by the coup countermeasures.

[citation needed] Some experts assert that the United States directly facilitated and encouraged the mass murder of hundreds of thousands of suspected Communists in Indonesia during the mid-1960s.

[38] Historian John Roosa, commenting on documents released from the US embassy in Jakarta in 2017, says they confirm that "the US was part and parcel of the operation, strategising with the Indonesian army and encouraging them to go after the PKI.

"[39] Geoffrey B. Robinson, a historian at UCLA, argues that without the support of the U.S. and other powerful Western states, the Indonesian Army's program of mass killings would not have happened.

[40]: 83, 179  During the height of the violence, U.S. embassy official Robert J. Martens provided lists containing roughly 5,000 names of high ranking PKI members to the Indonesian Army, which, according to Robinson, "almost certainly aided in the death or detention of many innocent people".