Christianity's Shifting Views on War and Peace Through History

How Christianity's Stance on War Evolved from Pacifism to Just War Doctrine

"Love Your Enemies!"—Pacifism is woven into the very fabric of Christianity. Yet the faith has never defined itself as unequivocally pacifist. In fact, radical pacifist movements were often marginalized or even persecuted within its ranks.

In Germany, the two major churches—Protestant and Roman Catholic—only began to fully embrace the principle of nonviolence, such as recognizing conscientious objection to military service, as a legitimate expression of Christian faith after World War II. Under the emerging paradigm of a "just peace," they also started to critically examine military approaches to security.

Russia's full-scale invasion of Ukraine in February 2022 forced Christian churches to once again confront the reality of military violence and their response to it. The following analysis focuses on Protestant perspectives while also considering parallel debates within Catholicism. It begins by outlining the formative developments of early Christianity, then explores the political ethics of the Reformation—an era in which the conflicts of the 16th century led to a rejection of strict pacifism. Next, it examines the turning point of the 20th century, when the horrors of totalitarianism and unrestrained warfare reshaped church teachings on worldly order, giving rise to a new peace ethics centered on the concept of "just peace." Finally, it asks how churches today should respond to the unexpected resurgence of large-scale interstate military aggression.

"But You Are Not to Be Like That!" The Early Christian Self-Understanding

The first Christians interpreted the life, message, and fate of Jesus of Nazareth as the fulfillment of biblical prophecies about an eschatological savior through whom God would definitively establish His unparalleled kingdom of peace. They saw themselves as a community called out of the world by the Spirit of this savior, united in a shared eschatological existence. This identity involved a deliberate rejection of social, cultural, and religious exclusion—embracing not only Jews but also Gentiles, not only the economically and politically privileged but also the poor and enslaved. It demanded an ethos of self-denial and nonviolence, starkly contrasting with worldly strategies of domination and self-interest.

This ethos was rooted in Jesus' own teachings, most vividly expressed in the Sermon on the Mount, where the Beatitudes declare peacemaking a defining trait of God's children and radicalize the commandment of love to include even one's enemies—renouncing self-defense and retaliation.

Of course, as the expected imminent return of Christ failed to materialize, early Christians had to redefine their relationship with the world. They could no longer simply withdraw; they had to prepare for an extended presence within it. From the beginning, political authority was not uniformly rejected—Paul, in Romans 13, even ascribed to it a God-ordained role, wielding the sword to maintain order. Yet while Christians prayed for their rulers, they generally avoided holding office or participating in governance. This was partly due to the social composition of early congregations, whose members largely came from marginalized backgrounds, but it also reflected a persistent sense of detachment from the world, reinforced by waves of state persecution.

A fundamental shift came with the "Constantinian turn" after 313 AD. Instead of suppressing Christianity, the state began to promote it. Rulers increasingly identified as Christians, seeing it as their duty to shape society according to Christian principles—and to defend the faith by political, even military, means. With this change, military service took on a new, affirmative significance.

Reassessing the Justification of War: A Christian Ethical Dilemma

This reassessment, however, brought with it the challenge of more precisely defining the conditions under which the use of military force could be ethically justified from a Christian perspective. It was no coincidence, then, that the late antique period—when Christianity was consolidating its dominance—saw the Christian adaptation and systematic development (most notably by Augustine) of the "just war" doctrine. Far from offering blanket justification for military violence, this doctrine instead served to restrict the legitimate grounds for war. Yet it was more than a minor flaw that Augustine included the spread of Christianity among these justifications.

Maintaining Order: Peace, Power, and the Reformers' Theology

By the 16th century, the Reformers largely inherited these foundational Christian principles but adapted them in key respects. The Peasants' War forced the Reformation movement to confront a pressing question: What means could—and should—be employed to shape, or if necessary uphold, socio-political order? On one hand, Reform-minded authorities faced pressure to demonstrate that introducing the Reformation would not, as their opponents claimed, lead to the collapse of law-based social structures. On the other, Reform theologians were challenged by peasants who, in resisting authority, invoked Luther's writings on Christian freedom. A separate but equally complex confrontation arose with the radical Anabaptist movement, which envisioned Christian existence as a community of the redeemed outside conventional society. Amid this tangled landscape, a fundamental question emerged: How should Christians relate to the sin-corrupted world? Should they withdraw from it entirely, or actively engage in shaping it?

The Reformers addressed this dilemma with arguments later systematized as the "Two Kingdoms" or "Two Governments" doctrine. Its core tenet: God engages with the world in two fundamentally distinct ways. His primary work is one of salvation, reconciliation, and redemptive love—achieved through the proclamation of the Gospel and realized in the individual's faith. Since faith cannot be coerced, this proclamation rejects external force. It is God's proper work (opus proprium) because it directly expresses His nature as love. The second mode of divine engagement, by contrast, is a "strange work" (opus alienum), one that presupposes human sin and responds to it in a damage-limiting way. To this end, God establishes secular authorities and institutions tasked with maintaining—or restoring—the external order necessary for flourishing human coexistence. The most critical of these order-sustaining bodies is the political government.

Given the destructive tendencies inherent in a sinful world, the legitimate tools available to political authority include the use of force when necessary to combat chaos and preserve or restore order. The Wittenberg Reformers thus declared that Christians were not only permitted to participate in shaping socio-political structures but were obliged to do so, as such engagement embodied the concrete expression of Christian love for one's neighbor.

When it came to war, Luther explicitly emphasized the responsibility of authorities to employ measured, proportionate means aligned with the goal of preserving order—implicitly invoking the criteria of the "just war" tradition. Within this framework, the Reformers made clear that "soldiers, too, may live in a state of blessedness," Footnote resolution [1] meaning military service was a "normal" vocation that could be pursued "without sin," as stated in Article 16 of the 1530 Augsburg Confession.

The Anabaptist Rejection of Violence: A Different Framework

The Anabaptist commitment to nonviolence is framed in a fundamentally different way. According to the Schleitheim Confession of 1527—a foundational and authoritative early statement of Anabaptist beliefs—they acknowledge secular authority as an order instituted by God, yet one that exists "outside the perfection of Christ." Since Christians are called to this very "perfection," they are to model their lives directly on Christ, who fled when offered earthly kingship, and thus avoid holding secular office. Central to their understanding is the passage: "The rulers of this world lord it over them... but it shall not be so among you"—words through which Jesus, in the Gospel of Matthew, forbade His followers "the power of the sword."

This self-conception stands in stark contrast to the idea of Christian responsibility for the world through active participation in secular governance. It undermines the very foundation of a political order shaped by Christian motives. When Lutheran reformers categorically rejected the pacifism widely embraced by the Anabaptists, they did so based on a radically different understanding of Christian existence in the world. The accusation was that the Anabaptists failed to recognize the "pre-eschatological" nature of the world—a world in which violence cannot be ignored. By leaping ahead to a "perfection" promised only for the future consummation, they were said to evade their duty to defend and protect their neighbors, even at the cost of their own lives, in the here and now.

Conversely, however, the Reformers' emphasis on shaping earthly order risked reducing the biblical promise of peace to a matter of subjective faith alone. The nonviolent imperatives of the Sermon on the Mount were then confined to the individual conduct of the "Christian person," without transforming the broader social reality in which the believer, as a "worldly person," remains bound by the functional demands of their vocation.

"War Should Not Be, According to the Will of God": New Beginnings in the 20th Century

It was only the horrors of Nazi totalitarianism and the "total" devastation of World War II that brought about a profound shift in at least three key respects:

First, these experiences forced a fundamental reassessment of political order, conditioning loyalty to authority and affirming that resistance—even defiance—could at times be not only permissible but obligatory. The semantics of obedience gave way to participation. It became clear that not every ruling power, as the Epistle to the Romans might suggest, is ordained by God.

Second, the global war unleashed by the Nazi regime—marked by unbridled violence and wholesale destruction—"denormalized" war itself. Conflict could no longer be accepted as a routine feature of international life. The first general assembly of the World Council of Churches, held in Amsterdam in 1948, declared succinctly: "War should not be, according to the will of God." This conviction was only strengthened by the dawning realization of the catastrophic potential of nuclear weapons.

Third, the pacifist traditions of the historic peace churches were no longer dismissed outright as heretical but recognized for their significance in Christian witness. This shift mirrored changes within the peace churches themselves: rather than framing their pacifism as a withdrawal from the world, they now presented it as an active force for shaping society—advocating a culture of nonviolence.

In postwar (West) German Protestantism, these developments led to profound shifts in ethical perspectives on peace—though never without fierce internal church debates. For the first time, conscientious objection was recognized as a legitimate expression of Christian faith, while church circles also voiced opposition to German rearmament. Though there was broad agreement that nuclear weapons must never be used, the question of whether they could be produced and maintained as a deterrent in the face of Cold War threats remained hotly contested. The 1959 Heidelberg Theses struck a carefully balanced compromise: military service and conscientious objection were framed as two "complementary" forms of Christian witness for peace, while the possession of nuclear weapons—solely to prevent their use—was deemed "still" acceptable.

The tension inherent in this compromise persisted within Protestantism and resurfaced dramatically in the early 1980s during the debate over NATO's dual-track decision. The 1981 peace memorandum of the Protestant Church in Germany (EKD) reiterated—with even greater emphasis on the "still" of the Heidelberg Theses—the justifiability of military deterrence given the global political realities. Meanwhile, the Moderamen of the Reformed Alliance (also an EKD member) issued an unqualified "no" to the logic of deterrence and arms buildup.

As this reorientation unfolded, the just war tradition itself came under increasing scrutiny—a trend that intensified after the Cold War for two key reasons. First, the end of the military bloc confrontation appeared to usher in a new, cooperative phase in global politics, where conflicts no longer needed to be resolved through war. Second, following the reunification of the EKD churches, the East German churches—deeply influenced by pacifism during the GDR era, in part as a means of distancing themselves from the SED state—gained significant influence. The just war doctrine now seemed to embody the very logic of normalized violence that was meant to be—and in principle already had been—overcome. Against this backdrop, both major German churches developed the concept of a "just peace." The Catholic German Bishops' Conference (DBK) adopted it in 2000, while the EKD followed in 2007 with its new peace memorandum, Living from God's Peace—Working for a Just Peace.

Unlike the DBK, the EKD explicitly declared the just war tradition obsolete. The focus shifted to civilian conflict resolution, particularly prevention. Central to this approach was trust in the peace-promoting effects of a rules-based international order, especially through multilateral institutions like the UN. The EKD carefully outlined four fundamental dimensions of a "just peace": "avoiding the use of violence, promoting freedom and cultural diversity, and alleviating poverty." Military interventions were not entirely ruled out but were redefined as "law-preserving force," analogous to domestic police operations.

The EKD Synod went even further in its final "Declaration" of November 2019, asserting the failure and lack of sustainability of military interventions over the past decade. It now focused exclusively on civilian conflict resolution, citing "positive experiences"—particularly the example of the "peaceful revolution in the GDR." The notion of "law-preserving force" was relegated to a historical position. The theological framework had also undergone a fundamental shift: no longer grounded in the two-kingdoms doctrine, it now centered on an ethos of discipleship explicitly modeled on "Jesus' nonviolence."

Russia's War on Ukraine Exposes a Long-Standing Gap in Ethical Reasoning

The war against Ukraine threw into stark relief a glaring omission in ethical debate—one that had already been apparent in 2019: the failure to address what should be done when armed conflict erupts despite all diplomatic efforts. That question could no longer be evaded.

Current Challenges in Church Peace Ethics

The debate within German Protestantism remains deeply divided. While some demand a self-critical "course correction" in the Evangelical Church in Germany's (EKD) peace ethics, others argue that Russia's military aggression only underscores the fundamental validity of nonviolence as a guiding principle.

In 2023, a detailed contribution to the discussion was published: "The Measure of the Possible," a study commissioned by the Protestant military chaplaincy but authored independently. Drawing on the two-kingdoms doctrine, it endorses peacekeeping that includes military preparedness and, where necessary, the use of force—as long as such measures remain unavoidable in a world marked by violence. At the same time, it explicitly affirms the vision of a "just peace." The Gospel's message of peace is not sidelined but remains a guiding horizon—both motivational and orienting—for all efforts to shape the world, continually renewed through the liturgical spirituality of worship.

The EKD's policy paper "A World in Disarray: Pursuing Just Peace," released in November 2025 after extensive preparation, deliberately builds on the foundational 2007 document but sets new priorities in light of recent experiences—particularly the vulnerability of rules-based order to interstate military aggression. In a direct critique of the 2019 Synod declaration, it elevates "protection from violence" to a "fundamental good" among the four dimensions of just peace outlined in 2007, arguing that only within a secure space can the other dimensions fully unfold. The paper also recognizes military peacekeeping as an expression of Christian responsibility in the world.

While pacifism is acknowledged as a legitimate personal stance, the text argues that it does not inherently represent a clearer testimony to the Christian peace message nor can it be universalized as a binding ethical principle for peace policy. Participation in military defense, it concludes, is not inherently at odds with Christian ethics.

When comparing the Protestant Church in Germany's (EKD) memorandum with the Catholic German Bishops' Conference's February 2024 "Peace Declaration"—published under the title "Peace to This House"—striking convergences emerge in their assessment of the political landscape. Both documents also share a theological orientation toward the concept of "just peace." However, the Catholic Church has never abandoned the doctrine of "just war" and thus has never fundamentally rejected the legitimacy of military means to secure peace. The "Peace Declaration" acknowledges that Catholic peace ethics draw from "two traditions: Christian-motivated pacifism, with its absolute prohibition of violence, and the critically conditioned justification of force, aimed at controlling and minimizing violence."

This implicitly contradicts the claim that Christianity, by its very nature and normative foundations, is a radically pacifist religion. Yet the declaration unequivocally emphasizes that "war can never be an instrument of politics or conflict resolution"—it represents "a total failure of humanity and contradicts God's will." Nevertheless, war remains "a reality of our world to which we must respond in an appropriate and responsible manner." And this response, the text makes clear, may indeed include military means if the overarching "shared goal" of all conflict engagement—to "overcome violence"—cannot otherwise be achieved in a given case.

More than the EKD memorandum, the Catholic "Peace Declaration" reflects on the specifically Christian and ecclesial contribution to fostering a culture of peace, placing particular emphasis on cultivating a personal ethos of peaceableness. This ethos, it argues, is symbolically embodied and performatively practiced in liturgy while also being nurtured through church educational initiatives. The document does not shy away from acknowledging that the credibility of the Church's witness for peace is undermined when it fails to heed its own teachings in practice. It also explicitly honors the peace-bearing dimension of ecumenical cooperation among churches.

From a Protestant perspective, one can only endorse these nuanced reflections and proposals. In terms of peace ethics, the two churches differ in their current positions, if at all, only in emphasis—not in substance. While the EKD memorandum was sharply criticized by Christian peace groups shortly after its release—accused of opportunistic "proximity to the state" and even of establishing a (heretical!) "military doctrine of salvation"—the reality is that neither the Protestant nor the Catholic Church has abandoned a supposedly once-held (and, in the critics' view, the only tenable) radical pacifist stance. Instead, both have rearticulated their long-standing, post-World War II positions in light of today's challenges. There is no question of a return to the glorification of war.

If the Church does not wish to be seen as a "counter-society", confining itself to countercultural or "prophetic" rebukes against the violence embedded in social and political realities, it must engage within society. It must articulate how, from a Christian perspective, the pressing forms of violence today can be concretely overcome—or at least contained. Both churches have taken up this task without losing sight of the ultimate horizon of the Gospel of peace. On the contrary, they have underscored its guiding and motivating power, as well as the peace-generating potential of authentically ecclesial practice—even while critically acknowledging their own failures in living up to these ideals.

Internally, statements like the "Peace Declaration" and the EKD memorandum serve to clarify the Church's self-understanding and encourage Christian commitment to peace. Externally, they bring a substantive Christian voice into civil and political discourse. Whether this voice translates the Christian Gospel of peace compellingly enough into the concrete realities of the world is open to debate. What cannot be denied, however, is that it is an authentically Christian voice.