Rorate Caeli: De Mattei: "Religious Liberty - or liberty for Christians?"
"Further, the right of being immune to coercion, or rather the fact that the Church does not impose the Catholic Faith on anyone, but requires the freedom of the act of faith, does not arise from a presumed natural right to religious freedom or a presumed natural right to believe in any religion whatever, but it is founded on the fact that the Catholic Religion, the only true one, must be embraced in complete freedom without any constraints."
This does not seem to explain why the act of faith cannot be coerced. Should it not be said that the act of faith, by its very nature, must be free? The will moves the intellect to assent to God as First Truth, and the will cannot be coerced.
Secondly, if one is motivated to assent to propositions of the Faith for a reason other than God Himself, then it would not be an act of Faith but of some other sort of belief.
Since Faith cannot be coerced or compelled and its object is Divine and it is an act possible only through God's grace, it falls outside the competence of human authority. Human authority may act to protect the Church but it cannot punish those who have deliberately rejected Faith, except in so far as they threaten the good of the community? Does the Church have the authority to punish those who have sinned in rejecting Faith? It seems to me that Aquinas is wrong on this point. Even if Christians are obligated to keep the Faith, once they have turned away from it, how can they be compelled to return to it? How can anyone but God move them to return to Faith?