Unbaptised infidels are not to be compelled by external force to receive the faith, since to believe belongs to the will; for they cannot be compelled by the Church, since they are not subject to her power, nor by civil society, which lacks spiritual jurisdiction. Still, they can be compelled not to hinder the preaching or practice of the faith in the places where they are by blasphemies, arguments and persecutions, since the Church has received from Christ the right of preaching everywhere. Indeed, they can be compelled by their rulers both to observe the natural law, including natural religion, since the right ordering of society is founded upon this, and also on certain occasions to hear the faith preached.

Baptised infidels can be compelled by spiritual and temporal penalites to return to the faith and to the Church, since by baptism they were made subject to the Church (Council of Trent, session 7, canon 14).

(Benedict Merkelbach, Summa Theologiae Moralis, I, 740)