Unlike Augustine, however, Aquinas lived within a recognizably Christian social order and, for that reason, approached the question of citizenship from a different angle. Whereas Augustine spoke of the theological foundations of citizenship, Aquinas, following Aristotle, thought of citizenship as a natural aspect of human life. Aquinas considered politics to be inescapable because, like Aristotle, he believed human beings were by nature social and political animals.

While human beings are the most socially and politically inclined of all animals, they are also the most physically needy, which helps to explain the human propensity to live in society. The household or family is the first natural society to which persons belong. Yet the good of the family is only partial, since its principal aim is to procure the necessary goods for survival. But even the family, which is ruled by economics or the art of household management, is incapable of providing for its every need. Aquinas thought the political community completed the family unit, because as the greater community it incorporates and subsumes all lesser communities to its own end.

Because human beings are rational animals, it is not sufficient merely that they live, but that they live well. Indeed, Aquinas contends that our natural disposition inclines us both “to know the truth and to live in society.” Following Aristotle, Aquinas believed that natural human flourishing could occur only within the political community, “the most perfect of all human societies.” Unlike the household, the political community attains a degree of self-sufficiency. While the end of the family is the promotion of life, the end of the political community is the cultivation of human virtue. This elevated good is “common” to all citizens. Aquinas bases his notion of citizenship on the type of virtue that develops either from “ruling and being ruled in turn.” The good habits instilled in those who live under well-ordered and just laws, which are significant, given Christianity’s transpolitical claim, represent authentic human goods. As a result, Aquinas views the common good as constitutive of the citizen’s “proper” versus private good. To be sure, Aquinas held that the natural perfection of citizenship was inferior to the supernatural perfection of God’s grace. Yet insofar as grace does not destroy but perfects nature, human spiritual perfection does not negate the legitimate, natural perfection of political life. Accordingly, for Aquinas, only the man who is “depraved, a beast as it were … or the man who is better than a man, a god as it were,” is capable of living outside of civil society.~ Marc D. Guerra, review of The American Myth of Religious Freedom

This is a helpful and, I think, fair summary of the Thomist view of politics. The incorporation of lesser, or more local, communities in all their integrity is a vitally important point, and it makes all the difference in distinguishing what I might call a traditionalist conception of the state from its rival, the total state.

This ‘traditionalist’ view emphasises the need for larger political organisms to be developed ‘from the ground up’ and would seem to militate against forms of consolidation and centralism imposing one scheme on a variety of communities. It is the difference between what one might call a conservative “socialism” in corporatism, Distributism or solidarism and the uniforming, levelling and desolating revolutionary socialism, which is to say all the difference in the world.

Perhaps if we think of larger political organisms as ascending steps in a political hierarchy, in which, as in a spiritual hierarchy, lesser orders are raised to perfection (in the sense that lesser orders are able to attain their proper end or completion, telos), the idea of prior obligations to polity and state might seem less onerous. Obviously, the existing state is nothing like this ideal, but perhaps this ideal will make the basic principle of such an obligation easier to accept.