Coup Atlas Research Database
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80009301948ConspiracyMilitary coup

Thailand, 1948 — military coup conspiracy

Thailand (THA)Southeast Asia, AsiaSeptember 30, 1948

Event Summary

At the end of September and beginning of October 1948, the Army General Staff Plot, an attempt by members of the Thai army general staff to overthrow the government of Field Marshal Plaek Phibunsongkhram, was uncovered and suppressed by the Coup Group that had returned Phibun to power. Phibun had resumed the premiership in April 1948 through the pressure of the powerful Coup Group, and his second government was almost immediately beset by rival factions, including officers connected to the ousted statesman Pridi Banomyong and to disaffected elements of the general staff who resented the dominance of Phibun's clique. When the plot was discovered around 1 October 1948, more than fifty army and reserve officers and several prominent supporters of Pridi were arrested.

The failed conspiracy was the first of a string of coup attempts against Phibun's second premiership, followed by the Palace Rebellion of February 1949 and the Manhattan Rebellion of 1951, all of which he survived until his own overthrow by Sarit Thanarat in 1957.

Researched Details

Researched

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

Target identified in Coup Atlas research: Field Marshal Phibunsongkhram survived the Army General Staff Plot; more than fifty officers were arrested
RESEARCHED NAME
Key figures
Plaek Phibunsongkhram (prime minister of Thailand, target)
Army general staff conspirators (plotters)
Supporters of Pridi Banomyong (arrested)

Sources

On 1 October 1948 the unsuccessful Army General Staff Plot was launched by members of the army general staff to topple Phibun's government but failed when discovered by the Coup Group.
SOURCE REVIEWED Wikipedia, Plaek Phibunsongkhram open source ↗
As a result of the discovered plot, more than fifty army and reserve officers and several prominent supporters of Pridi Banomyong were arrested.
SOURCE REVIEWED Wikipedia, Plaek Phibunsongkhram open source ↗
In October 1948 conspirators in the Army General Staff Plot to overthrow the government began being arrested.
SOURCE REVIEWED Wikipedia, October 1948 open source ↗
The Army General Staff Plot was one of several attempts to launch a coup against Phibun, including the Palace Rebellion of 1949 and the Manhattan Rebellion of 1951, all of which he survived until his overthrow in 1957.
SOURCE REVIEWED Wikipedia, Plaek Phibunsongkhram open source ↗

Editorial Note

Dataset date 30 September 1948 aligns closely with the Army General Staff Plot against Phibun, dated around 1 October 1948, which led to the arrest of more than fifty officers. Well documented. Dataset codes it a military coup conspiracy. Pairs with the Thailand 1947-11-16 record in this batch.

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
80009301948

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

Outcome and Target

Coup Atlas research identifies the target as: Field Marshal Phibunsongkhram survived the Army General Staff Plot; more than fifty officers were arrested.

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
⚑ This citation establishes the coded baseline record; use the claim-level sources above for the researched narrative.

Baseline Source-Document Entries

The Christian Science Monitor

“Siam Arrests Ex-Premier; Widespread Plot Alleged: Siam’s King Injured,” October 5, 1948

South China Morning Post

“ARRESTS IN SIAM: Former Premier Among Coup Suspects,” October 6, 1948

New York Herald Tribune

“Siam Arrests Ex-Premier: Former Ambassador to Britain Also Is Accused of Plot,” October 5, 1948

The Irish Times

“Siam Plot Uncovered,” October 2, 1948

The Times of India

“Siam’s Bloodless Revolt,” October 5, 1948

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 →

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