Carranza established a strong government in Mexico from 1917-1920 to confront economic, political, social and military crises, but he was later assassinated. Obregon and Calles then led the governments in the 1920s, with Calles remaining president until 1934 and continuing Obregon's policies. Calles enforced anti-clerical articles of the 1917 constitution, angering Catholic groups and sparking the violent Cristero Rebellion. He also created the National Revolutionary Party, later renamed the Institutional Revolutionary Party (PRI), which became Mexico's long-ruling single party. During the 1930s, Cardenas nationalized Mexico's oil industry, sparking tensions with the United States, before passing power to Camacho as president