 Obregón's stance toward the church appears pragmatic, since there were many other issues for him to deal with, but his successor Calles, a vehement anticlerical, took on the church as an institution and religious Catholics when he succeeded to the presidency, bringing about violent, bloody, and protracted conflict known as the Cristero War.The Cristero War of 1926 to 1929 was a counter-revolution against the Calles regime set off by his persecution of the Catholic Church in Mexico and specifically the strict enforcement of the anti-clerical provisions of the Mexican Constitution of 1917 and the expansion of further anti-clerical laws.A number of articles of the 1917 Constitution were at issue