In the years before the Spanish Civil War and during the conflict there was certainly a large amount of rhetoric against the left. Specifically, there was a Fr. Tusquets, who was a Catholic priest who wrote prolifically on the subject. Tusquets picked up on the Protocols of the Elders of Zion and synthesized what he called a "Judeo-Masonic-Bolshevik conspiracy" or a "Judeo-Muhammedan-Masonic-Bolshevik conspiracy" to destroy Catholic Spain and by extension Western civilization. Despite Spain having a very small Jewish population Tusquets' books were widely read and widely believed. There were other authors in Spain that wrote on very similar themes, and the idea that there was a connection between Judiasm, Masons, and Communism was fairly widespread.

Tusquets' book got a bit of a rebuke when Eugenio Pacelli removed the nihil obstat from the book. Not only was Pacelli the Cardinal Secretary of State for Pius XI, he was elected Pius XII in 1939. Also, Tusquets was offered a number of high level positions in Franco's administration after the war--all of which he refused. He backed off his earlier positions, but how much of his turnaround was sincere is up for debate.

What is not up for debate is the violence of the repression unleashed on all leftists in Nationalist Spain, which continued in Francoist Spain. Membership in leftist political parties--including communist parties--was a death sentence in some areas. The same can be said for union membership, being a teacher or doctor, holding an elected position in the Republic, or any number of other affiliations. The best book on the subject is Paul Preston's Spanish Holocaust, which details the Nationalist repression in horrific detail. Preston details Tusquets' thoughts in the same book. Jose M. Sanchez spends some time on the same subject in a section of his book, The Spanish Civil War as a Religious Tragedy, which covers the Catholic Church's history with communism quite well.