Decree against communism- Pope Pius XII in 1949

Decree of the Holy Office in 1949
Q.1 Utrum licitum sit, partibus communistarum nomen dare vel eisdem favorem praestare. [By chance is it licit to give name or to make favors to communist parties?] R. Negative: Communismum enim est materialisticus et antichristianus; communistarum autem duces, etsi verbis quandoque profitentur se religionem non oppugnare, se tamen, sive doctrina sive actione, Deo veraeque religioni et Ecclesia Christi sere infensos esse ostendunt. Q.2 Utrum licitum sit edere, propagare vel legere libros, periodica, diaria vel folia, qual doctrine vel actioni communistarum patrocinantur, vel in eis scribere. [By chance is it licit to publish, promulgate or read books, journals or leaflets which defend the action or the communist doctrine, or to write for them?] R. Negative: Prohibentur enim ipso iure Q.3 Utrum Christifideles, qui actus, de quibus in n.1 et 2, scienter et libere posuerint, ad sacramenta admitti possint. [Can Christians who perform the acts mentioned on n.1 and 2 be admitted to the sacraments?] R. Negative, secundum ordinaria principia de sacramentis denegandis iis, Qui non sunt dispositi Q.4 Utrum Christifideles, Qui communistarum doctrinam materialisticam et anti Christianam profitentur, et in primis, Qui eam defendunt vel propagant, ipso facto, tamquan apostatae a fide catholica, incurrant in excommunicationem speciali modo Sedi Apostolicae reservatam. [If Christians declare openly the materialist and antichristian doctrine of the communists, and, mainly, if they defend it or promumulgate it, “ipso facto”, do they incur in excommunication ("speciali modo") reserved to the Apostolic See?] R. Affirmative
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The Decree against Communism is a 1949 Catholic Church document which excommunicates all Catholics collaborating in communist organizations.
The Vatican, having been silent during the war on communist excesses, displayed a harder line on communism after 1945. The ruling followed suit to an earlier 1937 encyclical entitled Divini Redemptoris which was strongly critical of communism and its Christian variants.
The Holy Office issued several decrees, falling broadly into two categories:
Defence of Church rights regarding the ordination of bishops and Church activities, and, Condemnations of participation in Communist parties and organizations. On July 15, 1948, L’Osservatore Romano published a decree about communism, which excommunicated those who propagate "the materialistic and anti-Christian teachings of communism", which was widely interpreted as an excommunication of the Communist Party of Italy, which however, was not mentioned in the decree. The Sanctum Officium continued to issue condemnations:

1 Membership in communist parties, July 1, 1949

2 Excommunication of Bishop Dechet, February 18, 1950

3 Membership in communist youth organizations, September 28, 1950

4 Usurpation of Church functions by the State, June 29, 1950

5 Illegitimate state ordered ordinations of bishops, April 9, 1951

6 Publications favouring totalitarian Communism, June 28 and July 22, 1955

The decree was confirmed in 1959 by Pope John XXIII when it was announced that Fidel Castro was excommunicated for leading a Communist revolution in Cuba.
In relation to this decree, some Jewish intellectuals have expressed regret that a similar decree was not or could not have been published with respect to National Socialism. This sense of regret is part of an ongoing debate on the historical and political legacy of Pope Pius XII.

References

1 L’Osservatore Romano July 15, 1948

2 AAS 1949, 334

3 AAS 1950, 195

4 AAS 1950, 533:

5 AAS 1950, 601

6 AAS 1951, 217

7 AAS 1955, 455 and 558

Comments
Therefore, all catholic who votes for a communist party (which is a way to make favor) or who affiliates into a communist party, or who writes filo-communist books or magazines are excluded from the sacraments. Those who defend, promulgate or declare the materialism from the communists are also automatically excommunicated. This decree from Pius XII’s Holy Office, confirmed by John XXIII in 1959 is still valid. In fact, Pius XII worked personally against communism in Italy. Such a condemnation of communism adds up to other condemnations made by Pius IX, Leo XIII, St. Pius X, Pius XI, Pius XII (who have condemned it in other opportunities), John XXIII, Paul VI, the Council Vatican II (which reiterated the preceding condemnations) and John Paul II. It has been more than 100 years that the Catholic Church condemns communism, socialism and any kind of materialism and material egalitarianism. The penalty for those who disobey the prohibition of aiding communism (or its variants) under any aspect (including voting for filo-communist parties) is automatic excommunication. "Religious socialism, Christian socialism are contradictory terms, for no one can be, at the same time, good catholic and true socialist." (Pius XI)