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Aquinas and the State

A new book examines St. Thomas’s theory of the state, and the challenges it poses to the modern liberal order.

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St. Thomas Aquinas (Public Domain)

The Christian Structure of Politics: On the De Regno of Thomas Aquinas, by William McCormick, S.J. (The Catholic University of America Press, 2022), 272 pages.

Is there any contemporary relevance in De Regno, a thirteenth-century instructional manual on politics written by St. Thomas Aquinas for the young Norman prince of Cyprus? William McCormick thinks there is. Better known as On Kingship, it is the longest and only stand-alone practical treatment of politics by St. Thomas (1225–1274), yet it has attracted only sporadic interest from commentators over the centuries. More attention has been devoted to the better-known scholarly treatises of medieval Christendom’s deepest thinker. 


McCormick believes this neglect of De Regno is unjustified. The manual, he contends, offers a sustained rejection of civil religion and theocracy based on a theology of history not found anywhere else in Thomas’s corpus of writing. While it contains a desacralization of monarchy, the Christian ruler is characterized as a minister Dei under the church. Aristotelian political naturalism is affirmed while the differences between divine and human government are delineated. The familiar characteristics of tyranny listed here may remind readers of the perennial dangers of political despotism. How we are to deal with tyrants takes up only a small part of a text that covers many topics fundamental to the study of politics.   

McCormick’s scholarly study of De Regno argues that Thomas intended to provide a pedagogical tool—not a treatise—for the “intellectual and moral edification” of a head of state. The text, he notes, is an example of the practical application of theology. The author of The Christian Structure of Politics, a Jesuit priest and political scientist at St. Louis University, contends that the writing of De Regno was a political act by Thomas intended to win favor from the Cypriot king on behalf of his Dominican religious order whose missions were expanding into the Levant. 

McCormick disputes the claim that Thomas wrote a book of political theology, since appeals to history far outnumber scriptural references to kingship. Scripture by no means uniformly praises monarchy, and Aristotle, upon whom Thomas relies heavily, recognized the legitimacy of alternative forms of government. The author singles out for praise Robert Kraynak, whose scholarship locates where Thomas approves of various regimes based on prudential considerations. In other words, all legitimate political systems have strengths and weaknesses. Why then does Thomas favor monarchy uncritically in De Regno? The author contends that he “wants to predispose the king to take the duties of his royal office seriously.” By exalting the kingly office, says McCormick, Thomas is deepening the king’s obligations to justice. “[H]is elevation of monarchy is a rhetorical strategy, not a philosophical blindspot.”

Because politics is a natural activity, the king is not a minister of the church though he is a minster of God (Rom 13:1) and therefore subject to God. According to Thomas, just kings are minsters of God when they serve the common good. He follows Aristotle by elevating the nobility of politics beyond anything St. Augustine said in The City of God, in which the government is described as nothing more than a band of robbers. That being said, Thomas’s indictment of tyranny can be interpreted as a concession to Augustine’s darker vision of politics. Thomas knows that tyrants use fear and excessive force against their people to accumulate power and personal wealth. While the proper response is not tyrannicide, he admits that such unstable regimes are often overthrown. We should not expect perfection, however. Even the best regimes are flawed. An accurate understanding of human nature guards against political utopianism. 

One of the achievements of Christianity was to secure the independence of the church from the state. The final spiritual end of man—beatitude—is the responsibility of the church, a “distinct spiritual government,” not the state. On matters of religion, writes Thomas, “kings must be subject to priests.” Thus we are to give Caesar the things that are Caesar’s and to God the things that are God’s (Mk 12:17). There is no explicit relationship between church and state prescribed in De Regno. This, says McCormick, allows Aquinas to “valorize the integrity of politics” for the king, but also to emphasize the “superiority of the church” regardless of the political conditions. 


Gelasian dualism—named after Pope Gelasius I (d. 496)—distinguishes between the temporal and spiritual powers and gives primacy to the spiritual. The intellectual roots of dualism come from Aristotle, argues McCormick, while the superiority of the spiritual comes from Augustine. Thomas combined both into a coherent philosophy of politics but failed to satisfy objections from younger contemporaries such as John of Paris (1255–1306) and Giles of Rome (1243–1316). Lively debates like these debunk modern stereotypes that portray medieval Christendom as intellectually uniform. While Thomas does condemn civil religion and theocracy, elsewhere he does not oppose material assistance from the state on behalf of the spiritual mission of the church. McCormick gives these other writings of Thomas scant attention. Even in De Regno, he fails to draw obvious conclusions. For example, if De Regno really is a political document intended to curry favor from a Cypriot king, we might at least expect a request for armed security for the Dominican missions in the crusader-held territories of the Middle East. Practically speaking, what does it mean for the prince to defer to priests on matters of religion?

Gelasian dualism as advocated by Thomas was a direct challenge to civil religion that for millennia placed the responsibility of religion in the hands of temporal magistrates. McCormick rightly observed that civil religion is “an enduring feature of human community,” but he mischaracterizes as advocacy modern examples of Catholic resistance. “Crown and Altar” arrangements advanced by Joseph de Maistre (1753–1821) had nothing to do with divine-right-of-kings ideology famously advocated by Thomas Hobbes (1588–1679) on behalf of an Anglican Stuart monarch. De Maistre was a critic of the ancien regime and its Gallican articles as much as he was of the French revolutionaries of 1789. Those four articles imposed on the French church by Louis XIV in 1682 were, in De Maistre’s words, “the most miserable rag in ecclesiastical history.” McCormick rightly describes the medieval roots of modern Gallicanism as an early attempt by the French monarchy to found a “Christian civil religion.” He further reminds us that De Regno “contains one of the most trenchant rejections of civil religion within Christianity.” On this score, De Maistre, the father of ultramontanism, was more faithful to the Thomistic tradition than a string of pontiffs who had over centuries concede their spiritual sovereignty to the state. 

Gelasian dualism as advocated by Thomas was a direct challenge to civil religion that for millennia placed the responsibility of religion in the hands of temporal magistrates.

To what extent do these early debates matter to contemporary political arrangements? McCormick believes, based on an analysis by Jacob Levy, that the dualism advanced by Thomas directly challenges the liberal rationalism that increasingly dominates modern political life. The rationalism that originates from modern contract theory is not pluralistic and therefore denies dualism. Institutions that assert their sovereignty from the state are not tolerated. The church, therefore, is just one of many private institutions that are subordinate to a kind of modern monism that mirrors pre-Christian political arrangements. Rationalism favors rights of conscience over institutional rights and applies liberal standards to intermediate groups to prevent them from becoming sources of resistance to liberal hegemony. 

Two recent Supreme Court cases might help to illustrate the conflict between earlier twentieth-century precedent that sought to restrict religious liberty under an ahistorical and unconstitutional “wall of separation” doctrine justified by modern liberal rationalism and the current majority’s preference for religious pluralism embodied in the First Amendment. The Court's holding in Kennedy v. Bremerton School District allows voluntary religious expression on public property, while its holding in Carson v. Makin permits spending public money on parochial schools as long as the funds are distributed equitably. 

McCormick argues that liberal pluralism is compatible with, though not identical to, the dualism advanced in De Regno. The medieval aspiration to social pluralism provides a basis for a Christian rapprochement with modern liberal pluralism. The liberty of the church in McCormick’s view should be upheld by pluralists as a bulwark against “overweening” rationalism or statism. Religious freedom is always at risk as long as rationalism is an inherent characteristic of modern liberalism. Furthermore, a weak pluralism will not protect libertas ecclesiae from the danger of rationalism. Therefore, it is incumbent upon religious believers to defend liberal pluralism against its evil twin rationalism.

The world’s centers of power, especially in the West, are increasingly hostile to organized religion in general and Christianity in particular. The only practical recourse for religious believers living under this threat is to uphold and protect the principle of religious liberty. It is the pluralistic element of modern liberalism that McCormack believes is compatible with the Catholic philosophical tradition given expression in De Regno. However, there are pitfalls and dangers associated with modern liberalism not fully explored in McCormick’s study. A franker discussion of the intense debates among Catholic scholars over philosophical liberalism in the years leading up to the Second Vatican Council (1962–5) would have provided an opportunity to explore this subject in greater detail. The Council’s declaration on religious liberty, Dignitatis Humanae, left many questions unanswered. 

That being said, this debate over the danger posed to faith from secular liberalism is also an ecumenical concern by no means confined to the Catholic intellectual tradition. Despite these philosophical objections, religious believers have few options. The Western church has lost much of its political clout and cultural influence and must now work within the parameters drawn by its ideological foes. If liberal pluralism is the only recourse for religious believers, it must be preserved. Therefore, it is incumbent upon them to use all the intellectual resources at their disposal to ensure its continued longevity. William McCormick’s study can help Christians in particular apply the insights of one of Christendom’s greatest theologians to our contemporary political debates over how best to salvage what is valuable in liberal modernity.