Under Pope Francis’s guidance, Roman Catholic teaching on war and peace seems simultaneously near consensus and, vexingly, at an impasse. In a speech at the University of Notre Dame in 2023, Cardinal Robert McElroy sought to name the emerging consensus, yet also demonstrated how elusive it remains. Even while holding open the possibility of justified military action in “extreme cases” such as the Russian invasion of Ukraine, he argued that the just-war framework is not providing “an effective constraint on war or pathway to peace.” Strikingly, he affirmed that active nonviolence is now at the very center of Catholic teaching on war and peace. For it to be the center of Catholic practice, not mere teaching, however, nonviolence needs to be institutionalized.

The just-war tradition was supposed to reserve military action for truly exceptional cases of last resort while prioritizing non-lethal solutions. Thus, skeptics like those in Pax Christi International and the Catholic Nonviolence Initiative, who issued a now-famous “Appeal to the Catholic Church” in Rome in 2016, have reason to remain skeptical about the Church’s apparent pivot. Having called the Church to abandon just-war theory, they are not likely to retract that call just because what sometimes goes by the name “stringent just-war theory” gets a bit more stringent. Key to their argument is that supposed exceptions have broken down the theory’s fence too often and made war all too unexceptional.

Still, something is surely happening when a cardinal like McElroy and a pope like Francis consistently endeavor to shift the Church’s focus and change its accent. In the panel discussion that followed his speech, McElroy said he does not really like to speak of “just war” and simply wants to recognize that war might be justifiable in extreme situations. More significant than mere accent or nomenclature, the efficacy of nonviolence, as demonstrated in the groundbreaking work of Erica Chenoweth and Maria Stephan, was at the center of McElroy’s argument. Using social-science methodology to compile and analyze data from 323 resistance campaigns between 1900 and 2006, Chenoweth and Stephan’s 2011 book, Why Civil Resistance Works, shows that nonviolent movements have been twice as effective as violent ones at thwarting repressive regimes, and ten times as effective at putting in place durable democratic ones.

Our “new moment,” as McElroy put it, does not mean we’ve transcended Christianity’s long impasse over the ethics of war and peace, but, more modestly, that there are new opportunities to do so. On the one hand, nonviolent mobilization now has statistically significant evidence supporting it, thanks to scholars like Chenoweth and Stephan. On the other hand, responsible just-war thinkers have indeed become far more stringent since Pope John XXIII wrote his 1963 encyclical Pacem in Terris and the Second Vatican Council responded to the indiscriminate horrors of modern warfare by committing to a “completely fresh appraisal of war.”

How then to move forward and transform this “new moment” into a robust peace-building movement and unified Catholic Christian witness? As a theologian, it pains me to say it, but we probably don’t need more theology. As a signatory to the “Appeal to the Catholic Church,” it likewise pains me to break ranks, but I also doubt the wisdom of insisting that there can be no just war. If nothing else, such a claim risks alienating coalition partners who believe they can name at least one just war. Rather, we must build on our historical convergence concerning the injustice, inhumanity, and counterproductivity of almost all modern wars. The way forward is to shift our focus away from endless debates about theoretical exceptions to nonviolence and toward institutionalizing nonviolence in practice.

New institutions must draw on the history of nonviolent movements of civil resistance, which suggest a paradoxical relationship between improvisation and planning. According to Chenoweth and Stephan, strategic planning is a key element in successful nonviolent campaigns. Yet successful campaigns often start with improvisation. Their leaders are not necessarily principled pacifists or Gandhians to begin with; they are desperate yet pragmatic people. They include those who might have considered resisting violently but did not have the resources for expensive weaponry, or else intuited that direct military engagement would concede the advantage to their enemies.

Contrary to the oft-hurled and under-informed objection to peace movements, “But what about Hitler?,” nonviolent action was successful enough to pique imaginations even under Nazi occupation. Strategists of nonviolence, beginning with the late Harvard political scientist Gene Sharp, have not only mounted convincing responses to that standard objection but charted blueprints for civilian-based defense on national and continental scales.

Many examples of protecting Europe’s Jews have rightly gained attention. For example, Danes spirited more than seven thousand Jews across the channel to neutral Sweden on a single night in 1943. Though these rescues were local and generally too small to be more than suggestive of systematic nonviolent resistance, they were part of a much larger phenomenon, which has received surprisingly little attention.

Danes did more than rescue Jews. From 1940 to 1945, under Nazi occupation, they engaged in a program of active nonviolence involving multiple sectors of society, preventing the Germans from fully conquering the nation. When I taught a course on the ethics of war and peace, the Danish case study—which students first encountered in an episode of the PBS documentary A Force More Powerful—best illuminated the efficacy of nonviolence. To be sure, once one digs into the literature that informed the documentary, the case hardly proves unmixed or unambiguous. Nonviolent strategies were not only improvised at times but also intermixed with both violent sabotage by the armed Danish Resistance and tactical compromise with the Germans by the Danish government that formally ruled until 1943.

Still, the Danish example remains highly relevant for serious just-war thinkers and nonviolence advocates alike. What can we learn from partially improvised successes amid messy historical circumstances? And most importantly, given all that the Danes achieved nonviolently, even against the evil of Nazism, how much more would have been possible with earlier strategic planning and even a fraction of the institutional investment that societies put into military preparation?

The goal of a system of civilian-based defense is not so much to keep invaders from entering a national territory as to prepare its people to remain unconquered. Territorial self-defense is meant to come primarily through deterrence: the difficulty of controlling a stubborn and well-trained population becomes better known and gives pause to potential invaders. Remaining unconquered is what the Danish people achieved between 1940 and 1945.

When Germany invaded with little warning on April 9, 1940, the Danish government offered no military resistance. One Danish historian has called that decision a choice for survival over “heroic suicide.” Formally, the Danish government complied with the Germans and their pretense of protecting Danish sovereignty. Danish officials had to cooperate enough with the Germans to protect the populace without acquiescing entirely. But that did not mean surrender. Danes at every level of government used their own pretense of cooperation to slow-walk Nazi policies and stymie efforts to supply the German war effort with Danish agricultural and industrial products. Indeed, it was a tip from a Danish politician on friendly terms with a German industrialist that triggered the rescue of almost all of Denmark’s Jews.

Resistance from below was more pronounced. Danish antipathy towards the Germans predated the Nazis by centuries, such that even schoolchildren knew without being told that they should resist and harass the occupiers. A two-year-old when the Nazis invaded, my Danish uncle remembers little of the invasion except wave after wave of German airplanes rolling in. But as soon as he was old enough to run with his older brother and two of their friends, he became a wee saboteur. The little gang filled in foxholes dug for German patrols. They deflated German truck tires. They made great sport of throwing stones to break glass insulators on telephone poles in order to short-out the dedicated telephone lines that the Germans had strung up for themselves. “We did anything we could to aggravate them,” he told me, adding that some disgruntled German conscripts actually seemed amused. This hints at Sharp’s thesis that active nonviolence works by shifting support within the broad and compliant middle sector of societies.

Popular resistance was a wide phenomenon involving a continuum of tactics not always coordinated with one another. It was enabled by a unity that permeated all levels of the society, though careful historians rightly warn against mythologizing that unity. Nonviolent tactics ranged from strikes to songfests to protests disguised as commemorations, but they existed alongside the more militant actions of the capital-R Danish Resistance: caching of arms, underground coordination with Allied military forces, sabotage campaigns, and assassinations of Nazi collaborators. Even if Danes never agreed entirely on tactics, they were unified enough that support for Germany was fringe and the Danish Nazi Party remained tiny.

As various clandestine organizations coalesced into the Danish Freedom Council by 1943, even leaders of the armed Danish Resistance increasingly recognized that nonviolent actions such as industrial slow-downs and strikes were proving more successful than direct sabotage. Violence toward property is always a gray zone for both analysts and practitioners of civil resistance. The bombing of factories, train tracks, and other infrastructure marked the first years of Danish resistance but lessened as the war went on. The reason was not ethical scruples. Rather, industrial strikes and general strikes were proving harder for the Germans to crack down on. The German need for Danish products gave Danish workers more leverage than Danish commandos.

What’s more, whereas military action is always specialized, and underground cadres require even greater secrecy and limits on participation, nonviolent tactics drew together widening circles of Danes. Frode Jakobsen, a cofounder of the Freedom Council and eventual postwar leader, reflected the power of nonviolent civil resistance when he wrote to a member of Denmark’s government-in-exile in London: “The battle for our people’s soul is for me the most essential.... For me the problem must be: ‘How is one to draw the great mass of people into the fight?’ rather than ‘How is one to injure the Germans the most?’”

The Danish case is quite suggestive, yet it is only suggestive. Conditions vary in every historical situation, nonviolent civil resistance requires different tactics in different times and places, and not every civil resistance campaign will succeed. But all of this is true of military campaigns as well.

What the Danish case shows us is that the question “What about Hitler?” (or Putin, or Hamas, or whoever the next aggressor may be) should not derail collaborative efforts to carry forward our “completely fresh appraisal of war” toward completely fresh responses to violent human conflict. Whether or not “there is no ‘just war’”—as the 2016 Rome Appeal provocatively asserted—or only a few rare and exceptional ones, what we need is the training, commitment, heroism, and infrastructure that will make it easier to find creative alternatives short of any “last resort” to violence.

The ultimate goal is for nation-states to begin processes of what Sharp called “transarmament”—systematically planning for the kind of civilian-based defense that the Danes came to spontaneously. The transnational nation that is the Church, spread in diaspora across many nations, should not wait for nation-states, however. It must itself begin institutionalizing nonviolence, if indeed nonviolence is now “central” to its social teaching, as Cardinal McElroy suggested.

Through the Holy See’s Secretariat of State, the Vatican conducts the Church’s foreign policy, so to speak. For all kinds of reasons, we can thank God that it no longer has a military force. But maybe it should build up another kind of nonviolent “special forces unit” that learns from and scales up the work of grassroots organizations like Nonviolent Peaceforce, Violence Interrupters, Community Peacemaker Teams, and the John XXIII Community’s Operation Dove. These and other groups have been nonviolently accompanying vulnerable peoples for decades, defusing conflict around the globe.

If a nonviolent unit within the Holy See does not yet seem realistic, episcopal conferences and archdioceses could sponsor training in a whole range of practices, including peacebuilding, conflict transformation, and nonviolent crisis intervention. Perhaps these efforts would be most relevant in domestic contexts to begin with, but they would still help foster a Catholic familiarity with the power and practice of nonviolence. If Catholic churches did more to promote Mormon-style volunteer programs involving a year or two of Church and civic service, many young participants would surely want to become practitioners of nonviolence. Meanwhile, in the long term, just as Catholic leaders have engaged in politics, militaries, and think tanks for centuries, they could begin to advocate for and develop infrastructure for the transarmament of nation-states.

Of course, all of this will seem unimaginable until we start to imagine it. But the Danish case shows that such imagination is not baseless. It is an attempt to build upon and systematize past successes in active nonviolence.

Even stringent just-war theory requires the same commitment to institutionalizing nonviolence since only the full implementation and failure of nonviolence would make last resorts to violence operationally exceptional. Indeed, to begin with, the onus may fall primarily on those who affirm the just-war tradition, if only because they tend to be more embedded within existing institutional power. Nonviolence advocates tend, almost by definition, to be more marginalized.

Still, if this institutional transformation begins, a different onus will fall on nonviolence advocates. I sometimes ask my activist friends, “What will you do if you win?” In other words, are you ready to govern the changes you are calling for? Are you thinking about how to police nonviolently? Are you prepared for the hard—sometimes tragic—choices that those who manage institutions inevitably face? This, too, is a lesson from 1940s Denmark, where government officials were able to advance a largely nonviolent program of national self-defense only by remaining immersed in a morally ambiguous situation. Such ambiguities and dilemmas will accompany the institutionalization of nonviolence too.

Instead of drawing theoretical lines about exceptions in sand, then, let us work together to build a foundation on rock. That foundation can indeed be the one to which Cardinal McElroy has pointed: whatever exceptions do or do not arise, “the central point of reference for the Church on armed conflict” is now “comprehensive nonviolence.” Conceptually, that claim about Church teaching is irrefutable for those who take seriously the trajectory of the magisterium. Institutionally, however, active nonviolence is still far from “comprehensive” in the life of the Church. It is time to build.