Coup Atlas Research Database
← Back to explorer
85005081957ConspiracyMilitary coup

Indonesia, 1957 — military coup conspiracy

Indonesia (IDN)Southeast Asia, AsiaMay 8, 1957

Event Summary

The dataset records an event coded as a military coup conspiracy in Indonesia on 8 May 1957, during the mounting crisis of dissident army officers against the government of President Sukarno and army chief General Nasution. On 14 March 1957 Sukarno declared nationwide martial law, at Nasution's suggestion, in response to a wave of army-commander insurgencies including the Permesta movement proclaimed on 2 March 1957 and earlier military takeovers in the Sumatra provinces, which demanded greater regional autonomy, the removal of Nasution, a government less favorable to the Communist Party, and the banning of the party. This period of increasing unrest in the army and growing regionalism outside Java was marked by dissident officer plotting against the Sukarno-Nasution center.

The coded May 1957 conspiracy fits this pattern, part of the buildup to the CIA-backed PRRI and Permesta rebellion that erupted in February 1958.

Researched Details

Researched

Independent research, added record by record. Hover any label for what it means.

Target identified in Coup Atlas research: Sukarno and Nasution imposed martial law and later suppressed the regional rebellion by 1961
RESEARCHED NAME
Key figures
Sukarno (president of Indonesia, target)
General Abdul Haris Nasution (army chief, target of rebel demands)
Dissident outer-island army commanders (Permesta and Sumatra councils)

Sources

On 14 March 1957 Sukarno accepted army chief Nasution's proposal for a nationwide declaration of martial law to deal with the rebellious army commanders.
SOURCE REVIEWED Wikipedia, Guided Democracy in Indonesia open source ↗
The Permesta movement was declared by civil and military leaders in East Indonesia on 2 March 1957, and by then Sulawesi and most of Sumatra were in open defiance of the central government.
SOURCE REVIEWED Polynational War Memorial, Indonesia vs PRRI, Permesta and Darul Islam open source ↗
Developments in Eastern Indonesia and Sumatra were symptomatic of increasing unrest in the Indonesian Army and of growing regionalism in areas outside Java.
SOURCE REVIEWED U.S. State Department, FRUS 1955-57 vol. XXII open source ↗
The regional dissidents ultimately formed the PRRI in Sumatra on 15 February 1958, joined by the Permesta rebels, sparking a CIA-backed civil conflict that lasted until 1961.
SOURCE REVIEWED Wikipedia, Permesta open source ↗

Editorial Note

No discrete plot precisely on 8 May 1957 was found in accessible English sources this session; the entry records the dataset's coding and the verified context of dissident army-officer plotting under the March 1957 martial law, part of the buildup to the PRRI/Permesta rebellion. Flagged as context. Distinct from the 16 November 1956 Lubis affair in this batch and from the February 1958 PRRI declaration.

Cross-Reference

Only one dataset carries it. One of the three reference datasets we check against carries this event; the others do not list it. That is not a contradiction — the datasets cover different periods and use different thresholds — but it means the record has had less outside corroboration.

Identifiers for finding this same event in the other datasets:

Cline Center id
85005081957

How the match is made is described in crossref-report.md.

Outcome and Target

Coup Atlas research identifies the target as: Sukarno and Nasution imposed martial law and later suppressed the regional rebellion by 1961.

Baseline coding: Plot discovered and disrupted before execution. Recorded leader fate: remained in office; not physically harmed. The baseline file does not name individual targets; researched names are kept in a separate layer.

Baseline Dataset Citation
Cline Center Coup d’État Project Dataset, v2.2.2
Peyton, Buddy, Joseph Bajjalieh, Michael Martin, and Andrea Gerald. 2026. Cline Center Coup d’État Project Dataset. Cline Center for Advanced Social Research. V.2.2.2. February 17. University of Illinois Urbana-Champaign. doi: 10.13012/B2IDB-9651987_V10
Open dataset DOI ↗
⚑ This citation establishes the coded baseline record; use the claim-level sources above for the researched narrative.

Baseline Source-Document Entries

New York Times

“JAKARTA ARRESTS 21 Indonesian Army Officers Are Reported Accused of Plot,” May 11, 1957

Washington Post and Times Herald

“Coup Foiled On Java, Reports Say,” May 11, 1957

The Sun

“Plot Uncovered, Say Military In Jakarta,” May 12, 1957

This is the citation trail carried by the baseline dataset, grouped by outlet and rejoined from the line-wrapped original. Coup Atlas has not independently re-checked every document; read the original before citing a specific claim. URLs the import damaged beyond safe repair are shown as plain text and listed in citations-report.md. How this list is built →

Know something about this event?
Tips are reviewed against sources before anything is added.

Related Records

Indonesia — Military coup, 19561956-11-16ConspiracySoutheast AsiaIndonesia — Military coup, 19691969-12-19ConspiracySoutheast AsiaIndonesia — Military coup, 19521952-10-17AttemptedSoutheast Asia