When the assortment of Malay Peninsula states and the British colonies in Singapore and Borneo joined together to form the Federation of Malaysia in 1963, it’s large neighbour to the south, Indonesia responded by launching a policy of Konfrontasi (“Confrontation”) against the newly-formed state. The Konfrontasi took the form of both a diplomatic offensive and acts of military aggression against Malaya/Malaysia, targeted at it’s territory in northern Borneo.

An Asian subset of the Cold War
Various outside countries took sides in the Konfrontasi in an East/West alignment of powers transforming the conflict into yet another local arena for a proxy playing-out of the Cold War
▪ Malaysia was backed militarily by Britain and the Commonwealth (Australia and New Zealand), and diplomatically and materially by the US and Canada
▪ Indonesia got support from the two major communist powers, the USSR and mainland China, and from the Philippines and North Vietnam

Indonesia’s initiation of the Confrontation with Malaysia should be seen in the context of nation-building and the regional ambitions of the former Dutch colony‘s leader. President Sukarno, father of Indonesian independence, AKA Bung (“Brother“) Karno, saw the new Malaysian state as a neo-colonial appendageⓐ, a plot by the British to destabilise Indonesia (The Philippines held a similar view of Malaya). Sukarno’s own brand of socialism and his anti-western bent was sharpened by western complicity in sectional insurrection movements against the Indonesian state (giving aid to Permesta and Darul Islam rebels in their struggle against the government). Sukarno-inspired invective spoke of “crushing Malaysia” (Indon: Ganyang Malaysia).

Indonesia Raya, a Pan-Malay Union?
Indonesia’s nationalists had long nurtured a dream of Indonesia Raya, the creation of a “Greater Indonesia” uniting all the territories of ethnic Malays (see Endnote)… Sukarno’s objective was to wreck the Malaysian Federation and drive the British forces out, the realisation of which, it was hoped would allow Djakarta to establish a Greater Malay hegemony in the region led by Indonesia [Hindley, Donald. “Indonesia’s Confrontation with Malaysia: A Search for Motives.” Asian Survey 4, no. 6 (1964): 904–13. https://doi.org/10.2307/3023528]. An allied objective was territorial expansion, having earlier secured Irian Jaya through assertive brinkmanship diplomacy, Djakarta also harboured designs on adding northern Borneo to the republic [DVA (Department of Veterans’ Affairs) (2021), The Indonesian Confrontation 1962 to 1966, DVA Anzac Portal, accessed 24 May 2022, https://anzacportal.dva.gov.au/wars-and-missions/indonesian-confrontation-1962-1966].

An undeclared war
The Indonesia-Malaysia conflict never broke into open warfare but remained a limited engagement, a series of low-intensity border actions between the combatants. The military strategy adopted by the Indonesians comprised campaigns of infiltrations across the (Kalimantan/Borneo) border to make sorties on the Malaysian side. The Sultanate of Brunei—also viewed by Indonesia as a British puppet—was another target of Djakarta‘s subversive measures. Eventually the British retaliated with ”Operation Claret”, a sequence of counter-raids by small forces penetrating Indonesian Kalimantan which managed to keep the Indonesian forces on the back foot. Later Indonesia extended the conflict to the southern Malaysian mainland with a series of paratroop and seaborne raids.

Removing Sukarno
The conflict drifted into a stalemate through 1964 and 1965 while Japan, Thailand and the Philippines strived unsuccessfully to broker a peace deal [‘Konfrontasi (Confrontation) Ends’, HistorySG, www.eresources.nlb.gov.sg]. The ultimate circuit-breaker was domestic in origin, an ongoing power struggle involving the president trying to juggle the growing demands of the Indonesian Army on one side and the PKI (Indonesian Communist Party) on the other came to a climax in October 1965 with a failed palace coup. Army leaders used the incident as a pretext to carry out a mass purge of PKI (communist) members and leftist sympathisersⓑ – at least half a million were liquidated! President Sukarno was consequently discredited owing to his alleged close association with the PKI and eventually forced to relinquish power to General Suharto. Sukarno’s downfall took the heat out of the conflict…by August 1966 with Suharto’s “New Order” running the shop in Djakartaⓒ, Malaysia and Indonesia settled their differences with a peace treaty, bringing the Konfrontasi to a close with the sweetener of of desperately-needed US aid for the Indonesian state.

Endnote: Maphilindo, a still-born S.E. Asian association
The eruption of the Konfrontasi in 1963 killed a promising regional initiative stone dead. Filipino president, Diosdado Macapagal, convened a summit in Manila that year to propose a non-political confederation of Malaysia, Indonesia and the Philippines called “Maphilindo“…a long-held dream of Filipinos for union of states in the Malay Archipelago (Melaya irredenta – cf Indonesian aspirations)ⓓ. Suharto’s unilateral and uncompromisingly aggressive move squashed any hopes for close fraternal relations and mutually-advantageous cooperation in the region but Maphilindo did signpost the way to ASEAN which became a reality in 1967 [Pauker, G. J. (1964). Indonesia in 1963: The Year of Wasted Opportunities. Asian Survey, 4(2), 687–694. https://doi.org/10.2307/3023576].

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ⓐ when attempts were made to reach a resolution of the conflict Djakarta refused to negotiate directly with the “ puppet state“ of Malaysia
ⓑ a task facilitated for the army by invaluable CIA assistance (supplying communications equipment and lists of suspected communists to Sukarno) [‘What the United States Did in Indonesia’, Vincent Bevins, The Atlantic, 21-Oct-2017, www.theatlantic.com]
ⓒ and well and truly Cold War-aligned now with America in the anti-communist camp
ⓓ in the tri-state agreements Djakarta secured a coup getting Kuala Lumpur and Manila to agree that any Western bases (of which there were some on both Malaysian and Filipino soil) would not be be an indefinite fixture (Pauker)