The Cristero War occurred in Mexico during 1926-1929 under President Plutarco Elías Calles. It began with the enforcement of Calles’ anti-clerical ideology. Lay Catholics whom were angry with the enforcement of the anti-clerical laws of the Constitution of 1917 and the Calles Law rose up in arms against the Calles regime in 1926. Sporadic fighting occurred throughout the country. However, several months into the war, large-scale fighting only occurred in the central-west states. The majority of the war was fought under the leadership of the National League of Defense for Religious Liberty (LNDLR). The war ended in 1929 when the Mexican Episcopacy came to an agreement with the administration of Emilio Portes Gil. Approximately 250,000 people were killed during the war.
The cause of the war was the enforcement of the anti-clerical provisions of the Constitution of 1917. President Venustiano Carranza, the president during the creation of the Constitution of 1917, did not enforce the anti-clerical rules with much effort. President Álvaro Obregón actually tried to form some kind of relationship with the Vatican. However, President Calles enforced the anti-clerical provisions with ferociousness. During his term, he increased the repression felt the by the Catholic Church by passing the Calles Law. In response to his religious oppression, the Church responded with its religious strike. This led to the angering of the lay Catholics and the start of the war.
When President Calles became president in 1924, he enforced the anti-clerical laws of the Constitution of 1917. He was only able to enforce this at a state and municipal level when he began his anti-clerical policies. In response to his anticlericalism, many Catholic groups joined together to form the National League for the Defense of Religious Liberty (LNDLR) in March of 1925. On July 2, 1926, the announcement for the Calles Law was made. It would allow Calles to implement his anti-clerical enforcement on a national level and give the government the right to decide which religious buildings could be used for religious practice or which could be converted for use by peasant leagues, unions, and Revolutionary schools. The law would go into effect on July 31, 1926. After many failed attempts to negotiate with the government, the Mexican Episcopacy announced on July 25th that all priests would withdraw from their churches and religious services would be suspended starting July 31st. The Cristero War began within the few months afterwards.
The first few months of the war was characterized by economic boycotts. On January 1, 1927, the LNDLR called for armed action to overthrow the government. The Catholics that participated were referred to as Cristeros by the federal soldiers because of their war cry: “Viva Cristo Rey.” Before August 1927, the Cristeros operated in small and unorganized groups without a unified leader or military strategy. In August 1927, the LNDLR appointed two leaders. Jesús Degollado y Guízar was selected to be chief of operations in Colima, Nayarit, western Michoacán and southern Jalisco. Enrique Gorostieta was selected to take charge of organizing the rebels in northeastern and central Jalisco. He was later appointed to be the first chief of the Liberation Army in 1928. Under their command, the federal army was hard pressed in their efforts to stop the Cristeros. Most of the war was centralized in what is considered the Cristero central-west. This included states such as Jalisco, Guanajuato, Colima, Michoacán, Zacatecas, and Nayarit.
The Cristero War came to an end in 1929 because of two events. Foremost, Gorostieta was killed during a run in with federal troops on June 1, 1929. Following his death, Degollado y Guízar took over as the supreme commander of the Liberation Army. The second event was that the Mexican Episcopacy, primarily Archbishop Leopoldo Ruiz y Flores, came to an agreement with the administration of Emilio Portes Gil on June 29, 1929 under the mediation of U.S. ambassador Dwight W. Morrow. After the final agreement was made between the Church and the government, the Episcopacy condemned all Cristero rebellion and ordered all Cristeros to surrender to the federal army. Many rebels surrendered to the federal troops throughout the summer of 1929. However, in the face of the victory of coming to an agreement, the government did not change any of the existing anticlerical laws or constitutional provisions.