For those of you wondering if Communism is compatible with Catholicism, well, this document from the Vatican, in 1949, should clear things up...
Decree Against Communism
A question has been asked of the Supreme Sacred Congregation:
1. Whether it is lawful to be part of the Communist Party or to perform favors for the same;
2. Whether it is lawful to publish, propagate or read the books, periodicals, diaries or newspapers that defend the actions or the doctrine of the Communists;
3. Whether Christian faithful, who knowingly and freely committed an act mentioned in 1 and 2, may be allowed to receive the sacraments;
4. Whether Christian faithful, who profess, defend or spread the materialistic and anti-Christian doctrine of Communism as apostates from the Catholic faith, incur, ipso facto, excommunication reserved most especially to the Apostolic See.
To 1. Negative: for Communism is materialistic and anti-Christian; the Communist leaders, even if the words they profess do not attack the religion itself, in their doctrine and in their actions they show their fury against God, the true religion and the Church of Christ;
To 2. Negative: prohibited by the very law (1399 Code of Canon Law, 1917);
To 3. Negative: according to the ordinary principles of the sacraments, those who are not disposed are to be denied;
To 4. Affirmative.
Given in Rome, on July 1, 1949,
Supreme Sacred Congregation of the Holy Office