Thomas Massaro, S.J., is McGinley Endowed Professor of Religion and Society at Fordham University

As this essay is being written, it has been more than a month since the February 28 outbreak of hostilities between Israel and the U.S. (on one hand) and Iran (on the other hand). Public criticism of the war has been widespread. Political opponents (and even some normally supportive voices) have complained about the evident lack of planning, unclear objectives, and seeming disregard for the consequences of launching this “war of choice.” The shifting justifications for launching the war (including incoherent gestures toward the urgency of regime change and terminating Iran’s looming nuclear capability) have proven broadly unconvincing. The April 1 White House address of President Trump, broadcast in prime TV time, added little clarity.

The ordinary measures of the cost of any war (usually counted in “blood and treasure,” that is, in lives lost and military expenditures) are compounded by an array of regional geopolitical disturbances and economic repercussions stemming from disruptions in the global flow of petroleum. Any prolonged military action in the Persian Gulf will, of course, threaten closure of the vital Strait of Hormuz, through which one-fifth of the world’s oil production flows. That risk and its attendant costs were easily foreseeable, but inexplicably overlooked in the rush to war. American consumers and voters are always highly sensitive to the price of gasoline; the spike in fuel prices, exacerbating the already substantial burden imposed by high import tariffs implemented by the Trump administration, has prompted howls of protest from many quarters.

But economics and politics are not the only grounds for opposition to this military adventure. Howls of protest also emanate from those whose concerns primarily center upon morality and ethics. The war is not just an ugly, politically unpopular mess, but also one characterized by moral failure and ethical violations. The remainder of this essay will focus on moral objections to the war offered by religious leaders, and specifically by those of the Roman Catholic Church (the religion I know best), both within the United States and worldwide.

It will come as no surprise that Catholic leaders have voiced strenuous objection to this war, as it clearly does not meet the traditional criteria of the just war theory, which has long guided church reflection on warfare. (Objections from those who stand more solidly in the tradition of religious pacifism and nonviolence are also weighty but will not be treated here). The preemptive strikes on Iran (in the absence of any imminent threat) clearly violate even the most permissive interpretations of the just war approach. Most versions of just war thinking feature two sets of criteria for judging the liceity of any given military operation. The jus ad bellum criteria (gauging the justifications for initially entering a war) are clearly not satisfied, as the actions of Israel and the U.S. simply cannot accurately be characterized as a last resort, or as executed by competent authority (note the failure to gain the approval of the United Nations or even of a significant allied coalition in advance) or as conducted with right intention, among other ethical shortcomings. Nor has the conduct of the warfighting so far satisfied the jus in bello criteria of proportionality and discrimination (that is, prohibiting direct attacks on civilians). The tragically mistaken bombing strike upon an elementary school in southern Iran in the opening days of the war, with the loss of scores of innocent lives, many of them schoolgirls, is just one example of the toll in civilian lives and intense suffering that religious leaders routinely protest.

In the weeks since the war started, Catholic leaders at all levels—local, national, and global—have spoken out against the war, publicizing the moral judgment that it is a senseless, costly, and unnecessary war of choice. While such statements on public issues by individual bishops in their dioceses or by groupings of bishops (such as the United States Conference of Catholic Bishops, or USCCB) sometimes gain visibility, all eyes naturally fall on the Vatican, the center of global Catholicism. This is especially so now that, for the first time in history, a pope born in the United States occupies the Chair of Saint Peter. Indeed, the outbreak of this war has provided an opportunity for Vatican watchers to test out their theories regarding potential conflicts between the first American-born pope and an American president, the political leader of the world’s preeminent superpower. Specifically, a certain coterie of journalists has long been eager to see whether Pope Leo XIV would, upon provocation, openly rebuke President Trump for any of his objectionable domestic policies (such as harsh crackdowns on migrants) or questionable foreign interventions that violate Catholic values. Since the May 8, 2025, election to the papacy of the former Cardinal Robert Prevost, there have been occasions when the sharply differing approaches of the two men could have risen to the fore, but the pope’s calm, deliberate demeanor and measured approach to discernment have consistently defused whatever potential may exist for any sharp exchanges.

On those occasions when he has addressed the war in its first three weeks, Leo has issued broad calls for peace and diplomacy, expressing grave concern and appealing for restraint on all sides (including one to the media to avoid glorifying warfare and repeating the propagandistic messages of combatant parties). In doing so, he is employing vocabulary and tropes common in the papal playbook during wartime. Church historians identify a discernible lineage of consistent anti-war rhetoric that dates at least as far back as Pope Benedict XV (reigned 1914-22), a notable peace advocate who presided over the church with a palpable sense of heartbreak and agony during the conflagration of the First World War. Further, Vatican watchers note a strong and enduring preference among popes to avoid identifying the aggressors in any given conflict, as assigning such blame in public statements would undermine the potential for constructive papal efforts to mediate armed conflicts. (Pope Francis drew criticism for refraining from denouncing Putin’s Russia for its invasion of Ukraine in 2022, although it became clear that the pontiff understood the situation with clarity while straining to reserve a potential role for constructive Vatican diplomacy).

But Pope Leo is not the only potential Catholic voice of prominence, on either the global or the more local scene. In contrast to his deliberately quite generic commentary on the war so far, other Catholic prelates have spoken out more forcefully and specifically about ethical aspects of the current conflict. Filling the gap have been pronouncements of a number of Catholic bishops and especially of cardinals, both at the Vatican and in the United States. Cardinal Pietro Parolin, the Vatican’s Secretary of State, has naturally led the way in calling for a cessation of hostilities and the use of diplomatic channels to resolve the escalating conflict and defuse this highly dangerous regional fighting. Cardinals Domenico Battaglia of Naples, Italy and Pablo Virgilio David of the Philippines issued especially sharp rebukes of the decision to start this war and the methods of warfighting being employed. American Cardinals Robert McElroy of Washington and Blase Cupich of Chicago have been particularly outspoken against the continuation of hostilities. The latter issued a March 9 statement against the conduct of the war by the U.S., expressing indignation at the military’s tendency to treat war like a video game, with blindness toward the human consequences. Further, Defense Secretary Pete Hegseth has repeatedly invoked the rhetoric of Christian morality (or at least certain versions of it) to justify U.S. military operations as divinely sanctioned. Invoking the will of God in order to baptize modern warfare is morally objectionable, easily descending into blatant idolatry. The Catholic community, including not just bishops but academics and the Catholic press, has spoken out against such a stance repeatedly during this conflict. In a Palm Sunday address (on March 29), Pope Leo himself called for a cessation of all airstrikes in the region, and in a seeming rebuke to the specific practice of Hegseth in offering prayers for victory at Pentagon briefings on the war, issued this striking reproach: “God refuses the prayers of leaders who have hands full of blood.”

This last exchange is the rare exception to the general rule regarding how Pope Leo has handled the task of responding to public issues, as he very rarely engages political controversies head-on. Amid the vast majority of these public exchanges, some observers of the relationship between religion and politics have speculated about the strategy being employed by Pope Leo, at least in this instance involving armed conflict. Is he, in a sense, routinely employing “surrogates” to express his criticisms of the foreign policy of his native country, and of President Trump in particular, as a way of circumventing a more direct verbal conflict? The Vatican correspondent for one U.S. Catholic media outlet titled a March 12 article “Pope Leo Leans on Proxies to Condemn Iran War.” However, we understand the precise sequence of events in the rollout of Catholic opposition to this ongoing conflict; this episode provides insight into several aspects of the fascinating relationship between religion and politics. As history has repeatedly shown, religious leaders are frequently called upon to serve as voices of moral wisdom, especially in times of war.

The qualities of careful deliberateness and restraint being exhibited at the present moment by Pope Leo XIV may invite criticism, but they have proven valuable in past episodes of religious leadership, such as with the various prudent discernments of the Dalai Lama and Martin Luther King at pivotal moments in their respective efforts to safeguard oppressed people and advance social justice. Leo has good reasons to be eager to avoid directly responding to these and other actions of the Trump administration, as he has generally refrained from denouncing its policies in a direct and vocal way. Many find it awkward, and with good reason. That awkwardness was one of the several reasons why it was long assumed that successive papal conclaves would never select a pope from the United States, as long as this colossus was the world’s dominant power. The current tension between religious and political leaders is just the latest round in the millennia-long history of conflict between religion and politics. We have not seen the last of these.