[Je discute cette question dans un article a paraitre dans l'edition anglaise de Nova et Vetera; n'ayant pas le temps de traduire ces passages, je les donne en anglais]
There are two periods that were decisive for the formulation of Church teaching on these issues; the persecution and then the adoption of the faith by the Roman Empire, and the abandonment of the faith in Europe in the 19th century. The former period saw the development of a clear teaching on the way in which the state should assist the Church.
Both Empire and Church brought to their confrontation ideas about how religion should relate to the state. For the Romans, the worship of the gods was a matter of first importance to the state. The emperor, as pontifex maximus, was the supreme head of the pagan Roman priesthood, and as such was responsible for their proper worship. The power of Roman rule was held to depend on and stem from Roman fidelity in worship of the gods. Horace expressed this view in his Odes, 3.6, where he asserts ‘dis te minorem quod geris, imperas’ – the Romans rule because they serve the gods. Cicero asserted that it was only in piety towads the gods that the Romans excelled all other peoples (de Harusp. Resp. 19), and that disappearance of this piety would entail the disappearance of justice and social union (Nat. Deor. 1.4). Virgil in the Aeneid departed from his Homeric models by stressing the piety of its hero – a significant departure in a poem that furnished a principal ideological foundation for the Roman Empire. Dio Cassius, in the speech of Maecenas to Augustus recommending monarchy in book 52 of his Roman History, recommends that the monarch make the religion of state compulsory: ‘do you not only yourself worship the divine Power everywhere and in every way in accordance with the traditions of our fathers, but compel all others to honour it’1 - a view that followed Plato's position in Laws, book X, 907-912.
The Biblical teaching on religion and the state was the principal inspiration for Catholic teaching in this earlier period.1 In the Scriptures, the worship of all gods other than the God of Israel is forbidden, and the ruler is required to enforce this prohibition (see Exodus 32, Exodus 34:12-13, 2 Kings 23: 20, 25.) A rationale for this commandment is succinctly provided in Deuteronomy 32:17, which says of the rebellious children of Israel that ‘they sacrificed to demons which were no gods’. The God of Israel is the only true god, and hence the only being who should be worshipped; the other gods are not real gods, but are instead demons – ‘all the gods of the gentiles are demons’ (Ps. 95:6),2 a statement repeated in 1 Cor. 10:20, ‘what pagans sacrifice they offer to demons and not to God’. The banning of idolatry is not restricted to Jews: the worship of idols by Gentiles is condemned in the Old Testament (Isaiah 45:20, Psalm 115), and the commandment against idolatry is stated to apply to Gentiles in the New Testament (e.g. in 1 Cor. 6:9-10, with reference to Exodus 32:1, and Acts 15:20). Not only the worship of idols, but also any attempt to persuade Jews to worship idols, is to be punished by death; and any community that gives in to such persuasion is to be utterly destroyed (Deut. 13). Firmicus Maternus explicitly appealed to these biblical passages when he called on the Christian Roman emperors to suppress pagan worship 'with a truly Roman severity' in his De errore profanarum religionum.
Underlying this policy towards false religions is the Scriptural claim that the commandments of the first tablet of the Decalogue apply not only to individuals, but also to societies and rulers; and that the obligations to God that they refer to apply specifically to the God of Israel, and bind all rulers, not just Jewish ones (see Psalm 2:10-12).
In the Christian Roman Empire, the universally accepted position of both Church and Empire was that the state had a duty to uphold the true religion and to suppress the worship of false gods. A series of imperial edicts in the fourth century proscribed sacrifice to idols upon pain of death.3 In questions concerning the faith or unity of the Church, the position of both the Catholic Church and the Christian Roman state was that the Church decides, and the Emperor enforces. The position of the Christian empire with respect to the Catholic faith was given explicit legal form in the Theodosian Code, the sixteenth book of which legislates on religious matters. The book begins by stating that ‘It is Our will that all the peoples who are ruled by the administration of Our Clemency shall practice that religion which the divine Peter the Apostle transmitted to the Romans, as the religion which he introduced makes clear even unto this day.’4 The rationale for punishing heresy is given in title 5, 39, which states ‘We have recently published Our opinion in regard to the Donatists. Especially, however, do we prosecute with the most deserved severity the Manichaeans, and the Phyrgians and the Priscillianists. … it is Our Will that such heresy shall be considered a public crime, since whatever is committed against divine religion redounds to the detriment of all.’5 The enforcement involved the suppression of heretical and schismatic assemblies, the banning of heretical works and heretical preaching, and the imposition of various legal disabilities and other punishments on heretics and schismatics. St. John Chrysostom sums up the Catholic teaching on the punishment of heresy in the patristic era in his homily on the parable of the wheat and the tares in Matthew 13; ‘[Christ] does not therefore forbid our checking heretics, and stopping their mouths, and taking away their freedom of speech, and breaking up their assemblies and confederacies, but our killing and slaying them.’6 St. Ambrose, in the western Empire, considered that idolatry and heresy should be suppressed by the state (letters 10, 11, 24, 26, 57, funeral orations for Valentinian and Theodosius). Indeed, in his dispute with the pagan Symmachus over the restoration of the Altar of Victory to the Senate-house in Rome, he encountered and rejected many of the arguments for religious toleration that were to be revived in the 16th and 17th centuries (letters 17, 18).7'