Camilo Torres Restrepo, a Catholic priest ordained in 1954, was a known advocator of socialism, and eventually joined the National Liberation Army.
The encylical was hailed by the followers of liberation theology and socialist circles, as in it John Paul II acknowledged the existence of a great conflict of interest between capital and labor, and the class struggle employed as a means of resolving social injustice; in Centesimus annus from 1991, John Paul II went further and spoke of "positive role of class conflict when it takes the shape of a struggle for social justice.
(...) Pope John Paul II does much the same in many of his own messages, especially in his encyclical Laborem Exercens, where he uses, with perfect freedom and against the horizon of faith, categories he borrows from Marx: alienation, exploitation, means of production, dialectic, praxis, and so on.
A few weeks later, the pope himself seemed to endorse the movement when he wrote to the Brazilian bishops that as long as it is in harmony with the teaching of the Church, "we are convinced, we and you, that the theology of liberation is not only timely but useful and necessary.
[14] According to John Hellman, "Not long before he died, Lenin told a French Catholic visitor that "only Communism and Catholicism offered two diverse, complete and inconfusible conceptions of human life".
[16] According to a historian Elisa Carrillo, the Vatican was sceptical of "condemning any variety of communism", and Italian Catholics cooperated with Communists in the anti-fascist resistance.
After WWII, members of the Italian Catholic Action "saw no essential incompatibility between Marxism and Catholicism" and established close ties with Communists such as Mario Alicata and Pietro Ingrao.
The church made "no attempt to suppress or condemn the efforts of these young people to reconcile Catholicism with Marxism", and in 1943, Cardinal Luigi Maglione intervened on behalf of 400 Communist Catholics who were arrested for anti-government demonstrations.