Leo XIII on the State’s duties toward the Church

By Thomas V. Mirus ( bio - articles - email ) | Apr 15, 2026 | In Magisterium of Leo XIII

This is part of a series of articles and podcast episodes surveying the most important encyclicals of Pope Leo XIII.

Vatican II’s famous Declaration on Religious Freedom, Dignitatis Humanae, began by noting that its discussion of religious liberty “has to do with immunity from coercion in civil society” and so “leaves untouched traditional Catholic doctrine on the moral duty of men and societies toward the true religion and toward the one Church of Christ.” However, almost nobody who cites Dignitatis Humanae bothers to find out what that moral duty is, and thus they often interpret religious liberty in a way incompatible with Church teaching.

To correct this error, we would do well to read Pope Leo XIII’s encyclical Immortale Dei, “On the Christian Constitution of States” (promulgated November 5, 1885). However, we will need to be docile in approaching this teaching, as it is rather challenging to modern and American sensibilities. (Note that an audiobook of Immortale Dei is available for free on Catholic Culture Audiobooks.)

The argument of this encyclical proceeds from the starting point that the State, like the Church, receives its authority from God (Romans 13:1). Therefore, like everything that comes from God, the authority of the State must be subject to Him. Men, not just as private individuals but as communities and public authorities, are obligated to obey God, and this obedience cannot be limited to what can be known by reason. Since all truth is one and comes from the same Source, we cannot arbitrarily exclude revelation as binding on states. So, Leo says, the State has duties to profess, protect and foster religion, and not just any religion, but the true Faith:

The State, constituted as it is, is clearly bound to act up to the manifold and weighty duties linking it to God, by the public profession of religion. Nature and reason, which command every individual devoutly to worship God in holiness, because we belong to Him and must return to Him, since from Him we came, bind also the civil community by a like law…

Since, then, no one is allowed to be remiss in the service due to God, and since the chief duty of all men is to cling to religion in both its reaching and practice—not such religion as they may have a preference for, but the religion which God enjoins, and which certain and most clear marks show to be the only one true religion—it is a public crime to act as though there were no God. So, too, is it a sin for the State not to have care for religion as a something beyond its scope, or as of no practical benefit; or out of many forms of religion to adopt that one which chimes in with the fancy; for we are bound absolutely to worship God in that way which He has shown to be His will. All who rule, therefore, would hold in honour the holy name of God, and one of their chief duties must be to favour religion, to protect it, to shield it under the credit and sanction of the laws, and neither to organize nor enact any measure that may compromise its safety.

Leo’s teaching about the two societies of Church and State is essential to understand. The Church is a society “made up of men, just as civil society is”, but while civil society is ordered immediately to the natural and temporal good of man, the Church’s end is supernatural and spiritual. Thus the two societies have genuinely distinct spheres of authority, without one simply absorbing the other:

The Almighty, therefore, has given the charge of the human race to two powers, the ecclesiastical and the civil, the one being set over divine, and the other over human, things. Each in its kind is supreme, each has fixed limits within which it is contained, limits which are defined by the nature and special object of the province of each, so that there is, we may say, an orbit traced out within which the action of each is brought into play by its own native right.

Yet because these two societies share a common subject—man—their jurisdiction touches the same matters at times, though in different respects. Thus Church and State need to be in harmony so that they will not conflict in those areas where they overlap. Since the spiritual power is plainly superior to the temporal one, the proper harmony between them is compared to the union between the soul and the body in man:

One of the two has for its proximate and chief object the well-being of this mortal life; the other, the everlasting joys of heaven. Whatever, therefore in things human is of a sacred character, whatever belongs either of its own nature or by reason of the end to which it is referred, to the salvation of souls, or to the worship of God, is subject to the power and judgment of the Church. Whatever is to be ranged under the civil and political order is rightly subject to the civil authority. Jesus Christ has Himself given command that what is Caesar’s is to be rendered to Caesar, and that what belongs to God is to be rendered to God.

Leo expands upon the benefits of this harmony, especially the benefits bestowed upon civil society and the family by the Church. He especially praises the unparalleled flourishing of human civilization which occurred in Christendom “when States were governed by the philosophy of the Gospel”. Unfortunately, this harmony was progressively destroyed by Protestantism and then by erroneous philosophies—as regards the latter, he condemns liberalism and egalitarianism just as in his encyclical Libertas, already covered in this series. In particular, Leo describes the error of state secularism and absolute religious liberty:

Since the people is declared to contain within itself the spring-head of all rights and of all power, it follows that the State does not consider itself bound by any kind of duty toward God. Moreover, it believes that it is not obliged to make public profession of any religion; or to inquire which of the very many religions is the only one true; or to prefer one religion to all the rest; or to show to any form of religion special favour; but, on the contrary, is bound to grant equal rights to every creed, so that public order may not be disturbed by any particular form of religious belief.

And it is a part of this theory that all questions that concern religion are to be referred to private judgment; that every one is to be free to follow whatever religion he prefers, or none at all if he disapprove of all. From this the following consequences logically flow: that the judgment of each one’s conscience is independent of all law; that the most unrestrained opinions may be openly expressed as to the practice or omission of divine worship; and that every one has unbounded license to think whatever he chooses and to publish abroad whatever he thinks.

The negative consequences of the secular state for souls, for civil society, for marriage and the family, and for the suppression of the Church’s ability to influence society are laid out, along the lines of what he had detailed in Humanum Genus, already covered in this series.

Leo cites his predecessors Gregory XVI and Pius IX, reiterating their condemnation of state religious neutrality, as well as absolute freedom of speech:

From these pronouncements of the Popes it is evident that…it is not lawful for the State, any more than for the individual, either to disregard all religious duties or to hold in equal favour different kinds of religion; that the unrestrained freedom of thinking and of openly making known one’s thoughts is not inherent in the rights of citizens, and is by no means to be reckoned worthy of favour and support.

For the State to treat all forms of religion as equally valid, Leo says, is tantamount to atheism. Likewise the State must place restrictions on freedom of speech:

Whatever, therefore, is opposed to virtue and truth may not rightly be brought temptingly before the eye of man, much less sanctioned by the favor and protection of the law. A well-spent life is the only way to heaven, whither all are bound, and on this account the State is acting against the laws and dictates of nature whenever it permits the license of opinion and of action to lead minds astray from truth and souls away from the practice of virtue.

However, the fact that the State is obligated to support the true religion does not mean that it might not, for prudential reasons, tolerate false religions:

The Church, indeed, deems it unlawful to place the various forms of divine worship on the same footing as the true religion, but does not, on that account, condemn those rulers who, for the sake of securing some great good or of hindering some great evil, allow patiently custom or usage to be a kind of sanction for each kind of religion having its place in the State. And, in fact, the Church is wont to take earnest heed that no one shall be forced to embrace the Catholic faith against his will, for, as St. Augustine wisely reminds us, “Man cannot believe otherwise than of his own will.”

But that false religion might legitimately be tolerated, and that the Catholic faith cannot be imposed on anyone, should not be confused with a positive right to practice whatever false religion one chooses, such that pluralism is seen as a positive good. This is how the Church’s more recent teaching on religious liberty is commonly misinterpreted.

Readers might at this point be confused as to how the teaching of the nineteenth-century popes could, indeed, be compatible with Vatican II. The key lies in the limited scope of Dignitatis Humanae, which from the outset explicitly says it is addressing religious coercion by the civil power.

Because religion is a supernatural good, it is the Church, not the State, which has authority to regulate it. While the Catholic faith cannot be imposed on unbaptized people, the Church has authority to restrict the activities of false religions. As for Christians, the Council of Trent taught that the Church has authority to coerce the baptized in matters of faith. But none of this is within the authority of states acting on their own; they may only do so when directed by the Church, which is not presently the case. In this sense, the teaching of Dignitatis Humanae is an expression of the Leonine doctrine of the distinct spheres of Church and State.

But for more on these issues, I refer you to my interview with Thomas Pink. Rather than pairing this article, as usual in this series, with a solo podcast episode giving a longer summary, I’ve republished my 2020 interview with Prof. Pink about Immortale Dei. He gives a far richer discussion of the encyclical, its context, and how we should understand it in relation to Vatican II, than I could offer on my own.

Thomas Pink interview:

Immortale Dei audiobook: