Catholic political thought begins with assumptions familiar to many: (1) man is political by nature, and therefore political community is good for him; (2) because of natural human diversity of talents and capacities, authority is appropriate and natural to political community; (3) men have fallen and thus life in political community is marked by disharmony; (4) despite this disharmony and assisted by the guidance of authority, men in community can live together and work towards a shared good (a “common good”), and (5) all life is measured by conformity to the moral law contained in the natural law and illuminated by Christ. This includes life in community and therefore the exercise of political authority.   

Taken together these and other assumptions inform the way Catholics approach all questions of political theory and even very detailed questions about concrete living in any community at any time. Taken together they expose the folly in assuming that nonviolence is the only way of making peace. Indeed, taken together these assumptions argue against Catholic political thought ever abandoning the so-called “just war theory.”

Just war analysis follows from the acceptance of all five of the presuppositions of Catholic political thought. By analogy, the same moral framework applies to all other areas of moral life, including for instance medical ethics, the application of punishment (like war, a “use of force”), and economics. Just war thinking is practical reasoning applied to war waging. That is, in essence, all the just war account claims: the use of force associated with war must be governed by the same moral law that governs all of our lives.

As Elizabeth Anscombe long ago suggested, either politics is governed by morality or it is not. The Catholic view claims it is. The purpose of politics is the peace of the community served by those in authority. Those who exercise authority on behalf of a nation-state seek peace internally and externally. Internally this is obvious, if often poorly done: those in authority pass and enforce laws conducive to the common good of the community they represent. The people judge them on the basis of their performance on behalf of the common good. Within the nation-state, this governance is self-sufficient and essentially closed off from interference by external and competing sources of political authority.

But the nation-state’s sovereignty is not absolute. It is exercised within the boundary of the moral law, as we said, and likewise within the real international community of states of which it is a part and to which it has responsibilities. Just as politics guides the state internally towards the peace of its community, so too it guides the state towards the peace of the community of nation-states. Much more would need to be said about this, but Catholic political thought stipulates the existence of an international community of which states are parts. Nation-states possess sovereignty within this order, but only within it. In other words, their sovereignty is limited by the existence of the order within which they exist and without which they could not have the limited authority they possess. As members of this order, they have obligations to each other. Cooperation with other states in the maintenance of international order is an inescapable component of nation-states’ thriving. Catholic political thought thus rejects “national conservatism” in its understanding of nation-state independence and rule of law. 

Internally and externally, the exercise of political authority is sometimes coercive. In a fallen world, such peace as is possible can only be achieved by sometimes coercing those acting against peace. As the fourth assumption implies, a disharmony exists at every level of life in community, from family life, to life in the various communities we form local to us, to life in the enormous political communities of contemporary nation-states right up to the disharmony of the international community. Sometimes coercion is necessary to restrain or punish those who act contrary to the thriving of the community. Very few people actually deny this necessary role of coercion in life; most often, the denial stems from legitimate concerns about instances of coercion that seemed unjustified and excessive. In other words, general denials of the role of coercion usually piggyback on abuses of coercive authority, the abuses being pointed out by appeal to the very morality that explains and justifies coercion in the first place. The same is true for condemnations of the just war.

Some of the forecasting about the Church’s move away from this tradition of thought toward nonviolence is animated by concerns about abuses of authority and the misuse of appeals to just war terminology. In Fratelli Tutti (2020) Pope Francis said as much: “War can easily be chosen by invoking all sorts of allegedly humanitarian, defensive or precautionary excuses, and even resorting to the manipulation of information. In recent decades, every single war has been ostensibly ‘justified’.” (no. 258) He warns us to guard against the abuse of morality in the service of war.

Beyond the abuse of language justifying war, we can add concerns that have been raised since (at the latest!) the First World War. Modern wars are qualitatively different in scale of destructiveness. A combination of factors threaten the moral relevance of the critical distinction between innocence and guilt and soldier and civilian. Included among these factors is democracy itself; when moral support of war becomes explicit through voting, many conclude the relevance of the distinction between soldier and citizen null. The soldier’s just the poor sap “recruited” to carry out the will of the citizen whose vote brought the war upon himself. Why not punish both, then, especially since technology – drones, missiles, cyber – makes it easy? In addition, the economic, technological, and material interdependence of modern states makes every conflict at least potentially global, as we see again in Russia’s invasion of Ukraine. The end of peace is too hard to attain by contemporary war. And of course, atomic and nuclear weapons have introduced the reductio ad absurdum of technology: we have given ourselves the capacity to bring about an apocalypse. All war is waged under the shadow of potential nuclear catastrophe. The destruction of modern war strains the means-to-ends analysis necessary to regard war as an instrument of peace.

Together these amount to a rational case for exhausting all efforts short of war for vindication of right and maintenance or restoration of peace, something just war analysis has always insisted upon. Just war analysis demands this by scrutinizing the situation in which today the use of force is contemplated. Yet there remain those times when all other means fail and the reorganization of power requires force. These situations may indeed be quite narrow, as Pope Francis suggests, but he affirms their existence. “The Catechism of the Catholic Church speaks of the possibility of legitimate defense by means of military force,” he writes, “which involves demonstrating that certain ‘rigorous conditions of moral legitimacy’ have been met.” Just war analysis guides the entire process of seeking the means by which to maintain or restore peace.

Because the world is fallen, the peace we enjoy in the saeculum will always be some organization of power serving real but not ultimate goods, including the good of life in political community. The peace we enjoy is never more than provisional and never settled. The purpose of politics is to tame the power necessary in a fallen world, to imagine and pursue an organization of power more expressive of the goods of life in political community. Peacemaking, then, always requires subordinating power and harnessing the use of force in its service. Peacemaking, that is, always requires just war thinking.