14 Moreover, Venerable Brethren, in order to erect an effective bulwark against this extravagance of thought and extension of the spirit of independence, by Our authority, We absolutely forbid all clerics and priests to give their names in the future to any society that does not have Episcopal approbation. In a very special manner, under penalty of exclusion from Sacred Orders for clerics and suspension ipso facto a divinis for priests, We forbid them to become members of the National Democratic League, whose program was issued from Roma-Torrette on October 20, 1905. Its statutes were published the same year by the Provisional Committee of Bologna without the name of their author.
Source: Pieni L'Animo (Vatican.va)