On October 20, 1958, Field Marshal Sarit Thanarat carried out his second coup in Thailand, seizing full personal control of the government, abrogating the constitution, dissolving parliament, banning political parties, and imposing martial law. After his first coup in September 1957 had ousted Phibun, Sarit had gone abroad for medical treatment, leaving his deputy Thanom Kittikachorn as prime minister. Thanom's government proved unable to control the fractious governing coalition, especially its left-leaning members who opposed close ties with the United States.
Returning from treatment, Sarit removed Thanom, who resigned with his consent, and established an openly authoritarian regime, declaring a revolution and ruling by decree under an interim constitution. Sarit justified the move as a return to Thai traditions of order, launching a paternalistic dictatorship that lasted until his death in 1963 and entrenched military dominance for years.
Researched Details
Researched
Independent research, added record by record. Hover any label for what it means.
Target identified in Coup Atlas research: Thanom Kittikachorn, Prime Minister of Thailand (resigned as Sarit took direct power; not physically harmed, stayed in the ruling group)
RESEARCHED NAME
Key figures
Sarit Thanarat (field marshal who seized direct power)
Thanom Kittikachorn (prime minister who resigned)
Sources
When Sarit returned to Thailand in October 1958 he suspended the constitution, declared martial law, and imposed strict censorship, staging what is described as a self-coup after his deputy Thanom's government had struggled with unrest.
A U.S. State Department intelligence note dated 20 October 1958 reported the formation of a Revolutionary Council in Thailand that declared martial law, abrogated the constitution, and dissolved the National Assembly, taken with the support of Prime Minister Thanom Kittikachorn's government, which resigned; Sarit Thanarat headed the Council.
SOURCE REVIEWEDU.S. Department of State, Foreign Relations of the United States, 1958-1960, Vol. XV, Document 497open source ↗
In October 1958 Sarit, recently returned from medical treatment in the United States, took over personal control of the government with the consent of Thanom, who resigned as prime minister.
SOURCE REVIEWEDFacts and Details, "Vietnam War Period in Thailand" (citing Library of Congress)open source ↗
In October 1958 Sarit seized power in another coup d'etat, proclaimed an interim constitution, named himself premier, banned political parties, suspended constitutional rights, and jailed dissenters, establishing a highly authoritarian regime.
The Cline dataset codes 20 October 1958 (the FRUS intelligence note is dated the same day) with the leader not physically harmed, matching Thanom's resignation as Sarit took direct power. Two Wikipedia-derived sources, a primary FRUS note, and Britannica were read directly. This is Sarit's second coup, following the September 1957 record in this dataset, and it opened his outright dictatorship.
Cross-Reference
Datasets agree. At least two of the three reference datasets we check against carry this event, and none of them disagrees about its date or its result.
Identifiers for finding this same event in the other datasets:
Coup Atlas research identifies the target as: Thanom Kittikachorn, Prime Minister of Thailand (resigned as Sarit took direct power; not physically harmed, stayed in the ruling group).
Baseline coding: Incumbent executive removed from power. Recorded leader fate: deposed; 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
“Army Chief Seizes Power Thai Power Again,” October 21, 1958
“DIPLOMATS PRAISE THAILAND REGIME Economic and Political Acts of Premier Sarit Have Encouraged Westerners,” April 5, 1959
“Premier Sarit, 55, Dies in Thailand,” December 9, 1963
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 →