That the State must be separated from the Church is a thesis absolutely false, a most pernicious error.

Based, as it is, on the principle that the State must not recognise any religious cult, it is in the first place guilty of a great injustice to God; for the Creator of man is also the Founder of human societies, and preserves their existence as He preserves our own.

We owe Him, therefore, not only a private cult, but a public and social worship to honour Him.

– Pope St Pius X (Vehementer Nos: On the French Law of Separation)