Pius XI writes in the encyclical Dilectissima nobis (June 3, 1933):
“The Catholic Church is never bound to one form of government more than to another, provided the Divine rights of God and of Christian consciences are safe. She does not find any difficulty in adapting herself to various civil institutions, be they monarchic or republican, aristocratic or democratic.”
Plinio Corrêa de Oliveira, Nobility and Analogous Traditional Elites in the Allocutions of Pius XII: A Theme Illuminating American Social History (York, Penn.: The American Society for the Defense of Tradition, Family, and Property, 1993), Appendix IV, p. 394.