Various surveys show that, by 1940, the percentage of Catholics in good standing in Argentina was in the low two-digit range. From the rest, half were "occasional Catholics" that perhaps attended Church on religious holidays if ever. The other half did not belong to any religion (there were small minorities of religions other than Catholic). Today, the first percentage would be even lower. Most Catholics of lower and middle class interacted only with their parish priests and certain religious congregations. They did not much care about what their bishops of the Pope had to say about such matters such as divorce, birth control or children born out of wedlock. In general, Catholics of the upper classes were those that heeded the pronouncements of the hierarchy to the letter. They added to their religion many extraneous components such as "property" as a God-given right and privilege, and the "right" to use violence to keep it.
The Catholic hierarchy always acted on the false assumption that Argentines were overwhelmingly Catholic. The Church entered in marriages of convenience with different governments and the military; the payoff was imposition of (very ineffective) religious education in public schools, prohibition of divorce, etc. In the process the Church offered concessions that compromised its doctrine. It also condoned acts of increasing violence such as the bombing and strafing of civilians by Navy and Air Force planes in front of the Presidential Palace in June 1955. This was a failed effort to overthrow democratically elected President Juan Domingo Perón and caused more than 300 dead and thousands of wounded, many of them women and children.
Horacio Verbitsky (born 1942) is a top Argentine journalist. He was instrumental in investigating the torture and assassination of thousands of suspected militants and innocent bystanders perpetrated by the 1976-1983 military dictatorship, blowing the cover that the Church's hierarchy and the military tried to put on these atrocities under "forgive and forget" exhortations.
Cristo Vence (Christ Vanquishes) is the the first of four volumes on the interaction of the Catholic Church with successive Argentine governments. It covers the period from 1884 to 1955, the end of Perón's rule. The Church deeply mistrusted Peron's populism, but embraced him as an alternative to Communism, understood as a sickness/perversion that could be caught by the unwary. Over time the marriage Peron-Church soured and in September 1955 he was overthrown by a coup in which Catholics had a key role.
These four volumes are a monumental achievement. Verbitsky's investigative work involved consultation of thousands of sources, many in archives of difficult access, plus hundreds of interviews. The result is arranged with a light touch and sense of humor; once you begin this volume you'll find it difficult to put it down. The other volumes are La Violencia Evangélica (period 1955-1969), Vigilia de Armas (1969-1976) and La Mano Izquierda de Dios (1976-1983).