Coup Atlas Research Database
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09005181955ConspiracyMilitary coup

Guatemala, 1955 — military coup conspiracy

Guatemala (GTM)Central America, AmericasMay 18, 1955

Event Summary

The dataset records an event coded as a military and dissident coup conspiracy in Guatemala on 18 May 1955, during the first year of the US-installed dictatorship of Colonel Carlos Castillo Armas, who had taken power after the June 1954 CIA-backed overthrow of the reformist president Jacobo Arbenz. The Castillo Armas regime was beset by plots: soon after taking power he faced a revolt by young army cadets unhappy with the army's capitulation, suppressed with dozens of casualties, and in January 1955 his administration proclaimed it had unearthed a pseudo-communist plot being planned by regular army officers, responding with drastic measures including the execution of six of the men and the banishment of several leading officers. The regime was also near fiscal collapse, its foreign reserves having fallen from 42 million to 3.

4 million dollars by April 1955. The coded May 1955 conspiracy fits this pattern of anti-Castillo-Armas military plotting and the regime's harsh countermeasures.

Researched Details

Researched

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

Target identified in Coup Atlas research: Castillo Armas suppressed the plotting but was assassinated by his own guard in 1957
RESEARCHED NAME
Key figures
Carlos Castillo Armas (US-installed president of Guatemala, target)
Dissident regular army officers (plotters)
Young army cadets (earlier revolt)

Sources

Soon after taking power, Castillo Armas faced a coup from young army cadets unhappy with the army's capitulation, which was put down leaving 29 dead and 91 wounded.
SOURCE REVIEWED Wikipedia, Carlos Castillo Armas open source ↗
In January 1955 Castillo Armas's administration proclaimed it had unearthed a pseudo-communist plot being planned by regular army officers, executing six of the men and banishing several leading officers.
SOURCE REVIEWED Minnesota State University, The Results of the 1954 American Intervention in Guatemala open source ↗
By April 1955 the government's foreign exchange reserves had declined from 42 million dollars at the end of 1954 to just 3.4 million.
SOURCE REVIEWED Wikipedia, Carlos Castillo Armas open source ↗
On 26 July 1957 Castillo Armas was shot dead by a member of his own presidential guard in the presidential palace.
SOURCE REVIEWED Wikipedia, Carlos Castillo Armas open source ↗

Editorial Note

No discrete plot precisely on 18 May 1955 was found in accessible English sources this session; the entry records the dataset's coding and the verified context of anti-Castillo-Armas military plotting, with the January 1955 pseudo-communist plot purge and the earlier cadet revolt as the documented episodes. Flagged as context, distinct from the June 1954 coup. First Guatemala record in the dataset run.

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
09005181955

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

Outcome and Target

Coup Atlas research identifies the target as: Castillo Armas suppressed the plotting but was assassinated by his own guard in 1957.

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

New York Times

“GUATEMALA PLOT AIRED Five Men Are Jailed, One Man Gets Asylum in Embassy,” May 20, 1955

Washington Post and Times Herald

“Plot Is Charged In Guatemala,” May 20, 1955

Chicago Daily Tribune

“FIVE ARRESTED BY GUATEMALA AS PLOTTERS,” May 20, 1955

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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