Decree 900 in the context of "Guatemalan Civil War"

The 1954 Guatemalan coup d'état (Spanish: Golpe de Estado en Guatemala de 1954) deposed the democratically elected Guatemalan president Jacobo Árbenz and marked the end of the Guatemalan Revolution. The coup installed the military dictatorship of Carlos Castillo Armas, the first in a series of U.S.-backed authoritarian rulers in Guatemala. The coup was precipitated by a CIA covert operation code-named PBSuccess.

The Guatemalan Revolution began in 1944, after a popular uprising toppled the military dictatorship of Jorge Ubico. Juan José Arévalo was elected president in Guatemala's first democratic election. He introduced a minimum wage and near-universal suffrage. Arévalo was succeeded in 1951 by Árbenz, who instituted land reforms which granted property to landless peasants. The Guatemalan Revolution was disliked by the U.S. federal government, which was predisposed during the Cold War to see it as communist. This perception grew after Árbenz had been elected and formally legalized the communist Guatemalan Party of Labour. The U.S. government feared that Guatemala's example could inspire nationalists wanting social reform throughout Latin America. The United Fruit Company (UFC), whose highly profitable business had been affected by the softening of exploitative labor practices in Guatemala, engaged in an influential lobbying campaign to persuade the U.S. to overthrow the Guatemalan government. U.S. president Harry S. Truman authorized Operation PBFortune to topple Árbenz in 1952, which was a precursor to PBSuccess.

Juan Jacobo Árbenz Guzmán (Spanish: [xwaŋ xaˈkoβo ˈaɾβens ɣusˈman]; 14 September 1913 – 27 January 1971) was a Guatemalan military officer and politician who served as the 25th president of Guatemala. He was Minister of National Defense from 1944 to 1950, before he became the second democratically elected President of Guatemala, from 1951 to 1954. He was a major figure in the ten-year Guatemalan Revolution, which represented some of the few years of representative democracy in Guatemalan history. The landmark program of agrarian reform Árbenz enacted as president was very influential across Latin America.

Árbenz was born in 1913 to a wealthy family, son of a Swiss German father and a Guatemalan mother. He graduated with high honors from a military academy in 1935, and served in the army until 1944, quickly rising through the ranks. During this period, he witnessed the violent repression of agrarian laborers by the United States-backed dictator Jorge Ubico, and was personally required to escort chain-gangs of prisoners, an experience that contributed to his progressive views. In 1938, he met and married María Vilanova, who was a great ideological influence on him, as was José Manuel Fortuny, a Guatemalan communist. In October 1944, several civilian groups and progressive military factions led by Árbenz and Francisco Arana rebelled against Ubico's repressive policies. In the elections that followed, Juan José Arévalo was elected president, and began a highly popular program of social reform. Árbenz was appointed Minister of Defense, and played a crucial role in putting down a military coup in 1949.

Operation PBFortune, also known as Operation Fortune, was a covert United States operation to overthrow the democratically elected Guatemalan President Jacobo Árbenz in 1952. The operation was authorized by U.S. President Harry Truman and planned by the Central Intelligence Agency. The United Fruit Company had lobbied intensively for the overthrow because land reform initiated by Árbenz threatened its economic interests. The US also feared that the government of Árbenz was being influenced by communists.

The coup attempt was planned with the support of the United Fruit Company and of Anastasio Somoza García, Rafael Trujillo and Marcos Pérez Jiménez, the US-backed right-wing dictators of Nicaragua, the Dominican Republic, and Venezuela respectively, who felt threatened by the democratic Guatemalan Revolution, and had sought to undermine it. The plan involved providing weapons to the exiled Guatemalan military officer Carlos Castillo Armas, who was to lead an invasion from Nicaragua.