By: Fr. Brian Harrison O.S.
Vying with the Declaration on Religious Liberty for the honor (or disgrace, depending on one’s theological outlook) of being the Second Vatican Council’s most doctrinally innovative document is its Decree on Ecumenism, Unitatis Redintegratio (UR). Those at both traditionalist and liberal ends of the Catholic spectrum have seen this Decree (with sentiments of glowering gloom and gloating glee respectively) as representing a significant departure from traditional doctrine. The latter, of course, emphasized Catholicism as the one true religion, to which separated Christians will simply have to return if ever unity is to be restored. In this short article I shall limit myself to a comparison between UR and the pre-conciliar papal document most frequently cited as being incompatible with it, Pope Pius XI’s 1928 encyclical on fostering true religious unity, Mortalium Animos (On Religious Unity). This encyclical set out the Catholic Church’s position regarding the fledgling movement for religious unity which had been gathering steam in liberal Protestant circles since the late 19th and early 20th centuries.
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