In an open society, religion can be smothered simply by creating a climate in which religious believers are portrayed as buffoons and hypocrites, or as dangerous eccentrics. Or by setting ground rules of public debate that privilege a supposedly "scientific" outlook, and treat religious beliefs as irrelevant....
In the early Church, Christians said: "The Church belongs to God; therefore, she ought not to be assigned to Caesar." If those words are true -- and they are -- then we need to actively resist efforts by government to meddle in Church teaching and internal affairs, and to interfere with the life of her faithful. Vatican II's Declaration on Religious Liberty claims the autonomy of the Church in uncompromising language:
As the spiritual authority appointed by Christ the Lord with the duty, imposed by divine command, of going into the whole world and preaching the Gospel to every creature, the Church claims freedom for herself in human society and before every public authority. The Church also claims freedom for herself as a society of men with the right to live in civil society in accordance with the demands of the Christian faith.
The Church's freedom is never leased or bartered from Caesar. She takes part in the freedom of Jesus Christ himself. The council says that the relationship between the Church and Jesus is so intimate, that to restrict the Church's freedom of action is "to oppose the will of God."
Do read Archbishop Chaput's reflection in its entirety.