Catholic canon law has forbidden membership in Masonic organizations since 1738, with Pope Clement XII's papal bullIn eminenti apostolatus. Later popes continued to ban Masonic membership through the eighteenth and nineteenth centuries. When canon law was codified into the 1917 Code of Canon Law, these existing prohibitions were preserved in the code, especially in Can 2335. The 1917 code forbids Catholics, under the penalty of excommunication, to enroll in Masonic or other similar associations.
Can 2335: Affiliation With Masonic or Similar Societies. Those who join a Masonic sect or other societies of the same sort, which plot against the Church or against legitimate civil authority, incur ipso facto an excommunication simply reserved to the Holy See.
The 1983 Code of Canon Law superseded the 1917 Code. Specific mention of Masonry was omitted from the new code. Membership in organizations that "plot against the Church", however, is prohibited.
Can. 1374. A person who joins an association which plots against the Church is to be punished with a just penalty; one who promotes or takes office in such an association is to be punished with an interdict.
In the 1917 code, Masonry was specifically mentioned, but in the 1983 code it was not. Since the new canon law did not specifically mention Masonry, any issues or questions about Roman Catholics with Masonic associations were clarified by this document, which states that "the Church’s negative judgment in regard to Masonic association remains unchanged since their principles have always been considered irreconcilable with the doctrine of the Church and therefore membership in them remains forbidden. The faithful who enroll in Masonic associations are in a state of grave sin and may not receive Holy Communion."
Legal status
The relevance of the declaration under canon law is unclear. Canon law allows for a process by which provisions of the code are interpreted authoritatively. It has been argued, however, that the declaration cannot be regarded as an authoritative interpretation of canon 2335, prohibiting membership in organizations which plot against the Church, since it does not make reference to it. In addition, the declaration was not issued by the authority which issued the legal provision it interprets, which also casts doubt on the view that canon 2335 is interpreted authoritatively. It thus remains unclear, even under the declaration, whether membership in Masonry is, by itself, forbidden to Catholics under canon law.
Further analysis
For an analysis of how Bishops investigated Masonry and some their findings, see Letter to U.S. Bishops Concerning Masonry dated April 19, 1985 by Cardinal Bernard Law.
