A demonstrator holds a sign during a protest over U.S. strikes on nuclear sites in Iran, in Athens, Greece, June 23, 2025. (OSV News/Reuters/Louiza Vradi)
by Daniel P. Horan
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Last weekend, I was in Denver at the International Thomas Merton Society's biennial conference when I received The New York Times push notification that the United States, at the instruction of President Donald Trump, had bombed several targets in Iran.
Tensions had already been growing in the region as Israel continued its bombing campaign against Iran even as it was pursuing its attacks in Gaza. Leaders from around the world conveyed shock and concern at this development, many fearing that the violence would spill over into broader conflict in the Middle East and beyond.
Being in the company of more than a hundred Merton scholars and other enthusiasts for the writings of the American Trappist monk was a peculiarly fortuitous context in which to grapple with this disturbing military action. As many readers of National Catholic Reporter likely already know, one of Merton's major preoccupations from the late 1950s until his death in 1968 was peacemaking and war, especially the threat of nuclear war.
So, it was to Merton that I turned on Sunday as I journeyed from the Rocky Mountains back to my home in Indiana, rereading some of his essays on the themes of war and peace. I was hoping to gain some inspiration about how to think and what to do next.
Merton was writing in the wake of the nuclear attacks on Hiroshima and Nagasaki, Japan (the 80th anniversaries of those attacks are commemorated this August) and within the context of the Cold War and the Vietnam conflict. His reflections on international war and the Christian imperative for nonviolence may have been directed at conflicts more than half a century ago, but his insights continue to bear prophetic relevance today. He had a keen ability to name the structural sin not only abroad or against the "enemies" of the United States, but also turn his analytical lens back on himself and his context, inviting a national examination of conscience.
For example, in his 1961 book New Seeds of Contemplation, he writes:
When I pray for peace I pray God to pacify not only the Russians and the Chinese but above all my own nation and myself. When I pray for peace I pray to be protected not only from the Reds but also from the folly and blindness of my own country. When I pray for peace, I pray not only that the enemies of my country may cease to want war, but above all that my own country will cease to do the things that make war inevitable. In other words, when I pray for peace I am not just praying that the Russians will give up without a struggle and let us have our own way. I am praying that both we and the Russians may somehow be restored to sanity and learn how to work out our problems, as best we can, together, instead of preparing for global suicide.
Although much of the reference to Russia still, sadly, bears true today, especially in the context of the protracted invasion of Ukraine and the ongoing violence there, today we might also substitute Russia for Iran.
Members of Israeli forces work at an impact site following a missile attack from Iran on Israel, amid the Iran-Israel conflict, in Tel Aviv, Israel, June 22, 2025. (OSV News/Reuters/Violeta Santos Moura)
Another source of Merton's wisdom on war is the collection of correspondence known as the Cold War Letters, which he initially circulated among friends in the form of an uncensored mimeographed booklet. It was posthumously published in book form. The 111 letters written between 1961 and 1962 contain Merton's thinking about war and peace. The letters remain eerily relevant today.
In a letter to the Oxford theologian Etta Gullick, Merton admonishes those self-identified Christians who perpetuate global violence and delude themselves into thinking such action is compatible with Christianity.
"Those who think there can be a just cause for measures that gravely risk leading to the destruction of the entire human race are in the most dangerous illusion, and if they are Christian they are purely and simply arming themselves with hammer and nails, without realizing it, to crucify and deny Christ," he wrote.
Such a remonstrance echoes across the decades to indict today's politicians, church leaders and ordinary citizens alike who remain unmoved by the immediate and long-term effects of war and violence, especially on an international scale.
Coincidentally, Merton wrote to Ethel Kennedy, the mother of current Health and Human Services Secretary Robert F. Kennedy Jr., in 1961, about the "anti-moral response" in a lot of American politics. "It seems to me that there are very dangerous ambiguities about our democracy in its actual present condition. I wonder to what extent our ideals are now a front for organized selfishness and systematic irresponsibility."
In the same letter, he raised concerns about a kind of anti-intellectual bias growing in the face of complex cultural, social, and international dynamics. "I think it is going to be of greatest importance, in the next few months and years, if Americans can regain their healthy respect for reason, for the light of intellect, and get rid of this shallow contempt for 'eggheads.' They must learn to respect thought and stop idolizing psychopathic goofs."
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Merton's righteous criticism was not directed solely at public officials and the general citizenry; it was also aimed at church leaders and self-professed Christians. Again, to Kennedy, he wrote: "I personally wish the Church in America and everywhere were more articulate and definite about nuclear war. ... If as Christians we were more certain of our duty, it might put us in a very tight spot politically, but it would also merit for us special graces from God, and these we need badly."
This reference to being in a "very tight spot politically" makes me think of Catholics who currently hold high office, especially Vice President JD Vance and Secretary of State Marco Rubio, who have real power and authority in matters directly tied to the policies and actions of the United States regarding military force and violence.
Some in the administration have claimed that the attack on Iran was a limited, targeted and preemptive effort to stop the Iranians from developing a nuclear weapon, which they had still not yet succeeded in doing. Yet, even if the Iranian regime had functional nuclear capabilities, but had not targeted or deployed them, there is no allowance for so-called "preemptive" use of force in the Christian just war tradition.
Furthermore, as Merton writes in his posthumously published book Peace in the Post-Christian Era, "today the traditional idea of the 'just war' becomes fraught with ambiguities." He noted that the contemporary force of so-called conventional weapons of war and certainly nuclear weapons defy any ability to engage in a "limited war."
And even those uses of conventional weapons, such as those massive bombs deployed by American B-2 bombers in Fordo, can have devastating effects to life and property far beyond the "tactical" aims planned by military leaders.
As global violence continues to threaten the lives and freedom of people around the world, Merton challenges us in his essay "The Christian in World Crisis," to remember that "it is a special obligation of the Christian, who, as a follower of Christ, must be a peacemaker." The vocation to peacemaking is not for a select few, but for all the baptized, who are exhorted by Christ himself to be instruments of peace in a world of violence.
This is a difficult call, but one that is reiterated by Pope Leo XIV and reflected consistently in Merton's many writings on war and peace, which, sadly, remain as timely as ever.
