The Influence of the Roman Pontiff on Constitutional Theory

A Short(ish) Reflection

I was recently invited to contribute a chapter to a scholarly volume on the Constitutions of Microstates. I was specifically invited to contribute an essay on the Vatican City State and its Constitution, known as the Fundamental Law.

The Fundamental Law of Vatican City State is promulgated by the Pope, who exercises sovereign power over the territory. The Fundamental Law outlines how the Vatican City State is to be governed and the offices through which public power can be exercised in the name of the Pontiff. The Constitution is the foundation of all laws and regulations of Vatican City State, which are different from the legal regime applicable to the Roman Curia, which is the office through which the Pope exercises spiritual authority, and which is ruled by the Code of Canon Law. There have been three iterations of the Fundamental Law: the first promulgated by Pope Pius XI in 1929, the second in 2000 by Pope St John Paul the Great, and the third by Pope Francis in May 2023. The current Fundamental Law came into effect in June 2023. There is considerable continuity between each of these documents, and I will focus on the Fundamental Law currently in force.

In the preamble to the 2023 Fundamental Law the pope asserts that he has been “called to exercise sovereign powers” over Vatican City State by virtue of the “Petrine office” in order to guarantee the “Holy See’s absolute and visible independence” and its “sovereignty also in the international arena”. Another purpose of the Fundamental Law mentioned in the preamble is to constitute governing bodies to exercise functions and powers in service of the State. The preamble stipulates that the pope, when promulgating the Fundamental Law, does so pursuant to his enjoying the “fullness of sovereign authority” over the territory.

The Fundamental Law is comprised of five parts and twenty-four articles. Aside from guaranteeing fair procedures and natural justice during the judicial process, the Fundamental Law is solely concerned with the “nuts and bolts” of the governance of the State; by constituting institutions to exercise legislative, executive, and judicial functions on behalf of the Supreme Pontiff and structurally demarcating how each institution should interacts with the others.

I greatly enjoyed writing my contribution, and one of the themes I found most interesting, and which I try to tease out, is the extent to which the constitutional history of the Vatican City State and Pope has had a profound influence on Western public law and constitutional thought.

Many articles in the Fundamental Law of the Vatican City State will look familiar to comparative constitutional scholars, framed as they are using text and concepts now standard fare for a modern large-C constitutional document. But in fact, some of these seemingly bog-standard articles reflect concepts and ideas first honed and developed by the Catholic Church and papacy itself, in the precursor to the Vatican City State, during their long running contests with temporal authorities. Consider Article 1 of the Fundamental Law, which provides that the “Supreme Pontiff, Sovereign of the Vatican City State, has the full power of government, which includes the legislative, executive and judicial powers.” Elsewhere, in the preamble the Fundamental Law refers to the Pontiff enjoying the “fullness of sovereign authority” as the source of his ability to repeal the 2000 Fundamental Law and replace it with a new one.

The idea expressed in these provisions – of a juridical entity having power to make or unmake any law, to bind or unbind legal subjects – is of course now a settled (if constantly debated) part of constitutional theory. In perhaps most Constitutions, sovereignty is declared to be vested in ‘the People’, or a body corporate representing different elements of a people of a given territory, like the Crown-in-Parliament for the United Kingdom.

The precursor to this idea in Western political thought, of an entity enjoying the fullness of authority to set or vary legal obligations, comes to us in large part from the Church via Roman Law. In Roman law, the lex regia was used by jurists as a compendious legal concept to capture the effect and consequence of wholesale transfer of the Roman people’s natural power to govern themselves to the office of Roman Emperor. The lex regia was the font of other famous precepts like the Emperor being the living voice of law and justice; that the Prince’s legal determinations had the force of a statute (quod principi placuit legis habet vigorem); and that the Emperor was not bound by statutes nor answerable to any higher authority in the exercise of his functions (princeps legibus solutus). 

After the disintegration of the Western Roman Empire, the Church was key to the European rediscovery and revival of Roman Law in the eleventh century, most notably in its recovery of the Corpus Juris Civilis, and to the adaption and translation of its key legal concepts to articulate its own positions on important issues of authority and power. Concepts drawn from Roman jurisprudence provided a powerful conceptual tool for papal assertions of primacy over the Church and faithful in spiritual matters. One of the ideas adapted from Roman law was that the Church as the body of the faithful could be conceived in corporational terms, and that when it came to its internal governance and leadership, the Pope inherited by divine ordination as the ‘unworthy heir of St Peter’, the fullness of authority given to Peter over this body by Christ.

These powers were not vested in the natural person of the pope, but in the divinely empowered petrine officium which he unworthily occupied until his death, and which outlasted him. The Pope as the immediate successor to Peter enjoyed the fullness of power, plenitudo potestatis, over the Church; which encompassed power to make and enforce any law and adjudicate legal questions without being answerable to any other authority save God. Popes and supportive canonists and jurists invoked Roman law precepts associated with imperial power – including those referring to the Emperor’s plenary law-making power (quod principi placuit) and the fact he is not bound by the positive law (legibus solutus) – alongside arguments from scripture and tradition, to anchor their very active role in shaping and clarifying canon law and magisterial teaching, making uniform rules of behaviour for clergy across the whole of Christendom, disciplining and exhorting temporal rulers to abide by natural and divine law, and claiming ultimate say over the appointment and removal of clergy – all while claiming complete liberty from temporal direction.

Papal invocation of Roman law concepts and the fullness of power was a significant development in juridical thinking in the West for several reasons. First, it promoted the idea that law was not merely something that was customary, or something discovered or developed, but which could also be created, altered and repealed for the good of the body politic by an office with appropriate authority — an idea seized upon enthusiastically by popes through issuing decretals on a wide array of issues concerning canon or natural law and their adjudication of disputes from across Christendom, during which they acted as a kind of proto-supranational court of final appeal. Second, the fullness of power doctrine meant that the Pope was not answerable to anyone on this earth for exercise of his authority. In other words, like the Roman Emperor he admitted no juridical equal that could coercively call him to account for his use of potestas. Of course, it was universally accepted the pope was answerable to God for his tenure and decisions and to the directive force of natural and divine law, and would ordinarily judge according to positive law; but there was no temporal force that could sit in judgment of him – papa a nemine iudicatur.

These concepts and the Roman law sources that helped buttress them were eagerly embraced and translated by temporal rulers, who were keen to shore up their own authority. Holy Roman Emperors and their supporters who could chafe at papal assertions of authority to intervene in temporal affairs for reasons of faith and morals, would themselves heavily invoke Roman law concepts like the lex regia — indeed the concept of plenitudo potestas itself — to describe their own unassailable authority in the temporal realm. Kings eager to centralise their authority within their own dominion and over their noble class, began to claim enhanced lawmaking and tax-levying powers within their realm based on precepts drawn from the Corpus Juris Civilis.

Kings across Christendom also began to resist the idea they were de jure subject to the Holy Roman Emperor’s authority by asserting that, within the bounds of their kingdom, they exercised the fullness of temporal power of the kind enjoyed by the Emperor. In other words, rulers of powerful kingdoms like England and France, that were never really de facto subject to the Holy Roman Emperor’s control to begin with, began to assert that they were de jure akin to Emperors within their own domain – Rex in regno suo est imperator – and not subject to the jurisdiction of other rulers. Like the Emperor, they claimed to enjoy the lex regia from their people and the fullness of lawmaking power that came with it, acknowledging no temporal superior. They were even helped in this pursuit by canonist arguments building on the decretal Per Venerabilem issued by Innocent III, which observed without criticism that the “king of France recognises no temporal superior”.

The legal transfer of the Roman people of their natural authority to the Roman Emperor in perpetuity was the prototype, but came to be regarded as “universally applicable to the conditions of any regnum and every people” and ubiquitous in the legal writings of all European countries. In time, many European rulers would go one step further, and make the definitive break with the cosmological framing of the medieval world by arguing that, in the exercise of their governmental power, they were not subject to the direction of any higher authority, including the spiritual authority of the Church and papacy.

In contemporary liberal constitutional theory, the idea of political life being nested within and disciplined by reference to a broader cosmological and metaphysical hierarchy, is a dim memory at best; and temporal authority in Western Europe decisively rejects any subordination to the spiritual direction of the Catholic Church. Religion, says Martin Loughlin, is simply no longer the basic structuring force of collective organisation. That said, the ideas just canvassed continue to find expression in some of the most fundamental and foundational elements of public law thought. For instance, in the proposition that the People of a given state governing a territory enjoy the fullness of sovereign power to give to themselves, or to change, their form of government. Put in Romanist terms, as a juristic entity ‘the People’ in modern public law thought are Emperors within their own territory, enjoying full auctoritas to establish standing offices of government capable of channelling potestas to uphold the infrastructure of the state and its political right to pursue collective ends for the good of that people. Article 6 of the 1937 Irish Constitution offers a neat example of how this claim can be framed, providing that:

“All powers of government, legislative, executive and judicial, derive, under God, from the people, whose right it is to designate the rulers of the State and, in final appeal, to decide all questions of national policy, according to the requirements of the common good.”

They also find expression in the idea that this sovereign entity within a state, whether it be the People or Crown in Parliament, are not de jure answerable to anyone else outside of their territory for the exercise of their auctoritas or potestas, whether they be spiritual or other temporal powers. In other words, in juristic terms, each sovereign was to be regarded as on equal footing and free of the de jure direction of another, an idea which evolved to be considered a bedrock principle of international public law.

The development of the authority of the papacy, the creative mingling by the Pontiffs and their supporters of scriptural exegesis, Roman law precepts, and sophisticated political-theological argumentation, and the enthusiastic aping of these moves by temporal authorities, all helped provide some of the “basic grammar” of key concepts of modern public law.

To invoke Schmitt, the history of the Vatican City State highlights the extent to which many of the “significant concepts of the modern theory of the state” are best understood as “secularized theological concepts” that long predate the onset of modernity and rise of liberalism. These kind of insights are just some of the hidden treasures nestled within the terms of the Fundamental Law of the world’s smallest state.