Operation PBHistory was a covert operation carried out in Guatemala by the United States Central Intelligence Agency (CIA). It followed Operation PBSuccess, which led to the overthrow of Guatemalan President Jacobo Árbenz in June 1954 and ended the Guatemalan Revolution. PBHistory attempted to use documents left behind by Árbenz's government and by organizations related to the communist Guatemalan Party of Labor to demonstrate that the Guatemalan government had been under the influence of the Soviet Union, and to use those documents to obtain further intelligence that would be useful to US intelligence agencies. It was an effort to justify the overthrow of the elected Guatemalan government in response to the negative international reactions to PBSuccess.[1] The CIA also hoped to improve its intelligence resources about communist parties in Latin America, a subject on which it had little information.
The first phase of the operation began soon after Árbenz's resignation on June 27, 1954: several agents were dispatched to Guatemala beginning on July 4. These included agents of the CIA and the Office of Intelligence Research (OIR). The first phase involved the collection of 150,000 documents from sources including Árbenz's personal possessions, trade union offices, and police agencies. The ruling military junta led by Carlos Castillo Armas aided these efforts. Following a presentation made to US President Dwight Eisenhower on July 20, a decision was taken to accelerate the operation, and the number of people working in Guatemala was increased. The new team members posed as unaffiliated with the US government to maintain plausible deniability. The operation helped set up the Guatemalan National Committee of Defense Against Communism, which was covertly funded by the CIA: agents of the committee became involved in PBHistory. The team studied over 500,000 documents in total, and finished processing documents on September 28, 1954.
PBHistory documents were used to support the CIA's existing operations Kufire and Kugown, which sought to track Latin American communists and to disseminate information critical of the Árbenz government. Documents were also shared with the Kersten Committee of the US House of Representatives, which publicized PBHistory within the US. The documents uncovered by the operation proved useful to the Guatemalan intelligence agencies, enabling the creation of a register of suspected communists. Operation PBHistory did not succeed in its chief objective of finding evidence that the Guatemalan communists were being controlled by the Soviet government, and was unable to counter the international narrative that the United States had toppled the government of Jacobo Árbenz to serve the interests of the United Fruit Company.