During the Mexican Revolution, relations between Church and State were characterized by ideological differences and, paradoxically, by the pressing need for reconciliation on both sides. No single State policy toward the religious issue during this time can explain the true underlying aspects of these relations. Across this period of civil war the stance of caudillos such as Madero and Carranza sheds some light on how the Revolutionary State began to address its clerical policies. The Obregon (1920-1924) and Calles (19241928) administrations subsequently established clear anticlerical policies that led to the outbreak of the Cristero Rebellion and the violent Church-State conflict in Mexico from 1926 to 1929. In the first section of this essay I describe how the attitudes of caudillos and landmark historical moments shaped State policies towards the Catholic Church, from the outset of the Mexican Revolution in 1910, to the eve of the Cristero Rebellion in 1926. I then examine the period in which General Calles' anticlerical ideals exercised a tremendous amount of influence on his administration's religious policy. In the final section, I analyze how United States officials meshed their diplomatic duties with outright involvement in the Mexican religious conflict.