Before Julius Caesar crossed the Rubicon, he won a different sort of contest: election as pontifex maximus, chief priest of Rome. No one at the time found this strange. In the ancient world, the man who commanded the legions also tended the sacred fires; the authority that built roads regulated rites. Altar and empire were one office.
Then, at Caesarea Philippi, something new entered history. Christ handed the keys of the kingdom not to the emperor, not to the Sanhedrin, but to a Galilean fisherman. Spiritual authority went not to Caesar, but to Peter.
That break, and what it means for religious freedom in America, is the subject of my conversation on Acton Line with William J. Haun, Senior Counsel at the Becket Fund for Religious Liberty and author of the forthcoming book Not to Caesar, but to Peter: Remembering Why the Catholic Church Is a Perfect Society (Angelico Press).
Haun’s argument revives a concept most Catholics have forgotten and most Americans have never heard: the Church as a societas perfecta, a “perfect society.” He draws especially on Pope Leo XIII’s 1890 encyclical Sapientiae Christianae.
“Perfect” here is an Aristotelian term of art. It means complete: a society that possesses, in itself and by itself, all the means necessary to achieve its distinctive end of leading souls to eternal life with God. It does not mean that the Church’s clergy or laity are sinless. The Church is perfect in her constitution, not personnel. Anyone who has sat through a parish council meeting can tell the difference.
Why does this matter? Because the alternative frameworks on offer are inadequate to what the Church actually is, and dangerous to religious liberty besides.
Modern law and modern habits of mind tend to treat the Church as one voluntary association among many: a club, a nonprofit, a Rotary chapter with incense. Haun argues that this framing quietly makes religious practice a matter of state permission. If the Church is just another association, her freedoms are just another set of exemptions, granted today and revocable tomorrow.
The older teaching offers a firmer foundation. If the Church is a complete society with her own origin, her own end, and her own governance, then her independence is not a carve-out from state power but a structural boundary on it. The existence of an institution that answers to a higher authority than Caesar is itself a check on Caesar’s pretensions. This is why, as Haun notes, even non-Catholics have a stake in the argument: religious freedom grounded in the nature of the Church is far more durable than religious freedom grounded in the state’s forbearance. This argument is strikingly similar to the one advanced by Lord Acton in his 1877 lecture “The History of Freedom in Antiquity”, and it is an excellent one.
Haun is equally careful to distinguish his thesis from its counterfeit. Contemporary neo-integralists propose to direct society toward Catholic ends by capturing state power. Haun’s points out that whenever throne and altar have merged, it is the altar that gets subordinated. The regalist experiments of early modern Europe did not produce a sanctified state; they produced a domesticated Church, an instrument of governance rather than a proclaimer of the Gospel.
His counter-model is integration from without, and his exemplar is Archbishop John Hughes of New York, “Dagger John”, who met nineteenth-century nativist hostility not by seizing the levers of civil power but by building: schools, colleges, charitable institutions, legal protections. A Church confident in her own completeness enriches public life organically, from her own resources, on her own authority.
Haun closes with counsel in the same spirit: live the liturgical calendar, build the institutions, let the Church demonstrate her authority the way she always has through concrete practice.
Centuries after Caesar held it, the emperor Gratian declined the office of pontifex maximus, laying aside the old pagan priesthood. The title did not vanish. In time it settled where the keys had already gone, on the successor of the fisherman, the bishop of Rome. Caesar’s most ancient religious office now belongs to Peter’s heir.
Titles, like authority itself, eventually find their proper home. Haun’s book is a timely reminder of where that home is, and why remembering it may be the surest foundation religious liberty has.