I first met Michael Walzer about a decade ago. I was a nobody graduate student from Catalonia, finishing my dissertation. Walzer was a professor emeritus at the Institute for Advanced Study, in Princeton, and the former co-editor of the left-wing magazine Dissent, but he was most interesting to me as a philosopher—and, especially, as the author of “Just and Unjust Wars,” an attempt to delineate the rights and wrongs of warfare in both its causes and its conduct. In the nearly fifty years since it was published, no other book on the subject has matched its influence. I e-mailed him out of the blue, eager to discuss its ideas, and he invited me to his office. We talked about philosophy and politics on a walk in some nearby woods.
I returned to his work several years later, when a publisher wrote to me about another of his books, “Thick and Thin: Moral Argument at Home and Abroad,” which I had praised in a talk. They had acquired the rights to publish it in Catalan and asked me to write a prologue. I said yes, but found that I also wanted to write about Walzer’s career and his legacy. I wrote to him again, this time as a journalist, proposing a profile. Early in 2023, he invited me to his apartment, in New York, where he had just moved with his wife of nearly seventy years, Judy Borodovko Walzer—like him, a retired academic. In May of that year, Walzer and I sat in their kitchen and talked amid boxes waiting to be unpacked and paintings waiting to be hung.
He had recently turned eighty-eight. Walzer has a gentlemanly demeanor and a sense of irony that makes him difficult to pin down; he dislikes abstraction and hypotheticals, and prefers to speak and write without jargon. He learned to read, in the early nineteen-forties, from the left-leaning afternoon paper PM, he told me, which, he added, “had the best maps” of the Second World War. He remembers his grandmother rejoicing at the Soviet victory in the Battle of Stalingrad. His parents, the children of Jewish immigrants, were living in the Bronx, where his father worked in a defense factory. Later, Walzer’s father got a job, through his in-laws, at a jewelry store in Johnstown, Pennsylvania, where the family joined a Reform congregation. The rabbi was a Zionist, and Walzer shared a memory—though he wasn’t sure if it was accurate—of his parents weeping with joy listening to the news that the United Nations had voted in support of creating a Jewish state in what was then the British mandate for Palestine. In Johnstown, Walzer went to a consolidated high school, with kids from the well-to-do borough of Westmont and from the working-class township of Upper Yoder. After graduation, “half the boys” went to college, he said, and half went to fight in Korea. “It was a lesson in the class system,” he told me. He went to college at Brandeis, then did a Ph.D. at Harvard.
After Korea came Vietnam. When the United States sent combat troops, in 1965, Walzer was teaching political theory at Princeton, where he helped organize one of the first teach-ins against the war. The following year, he returned to Harvard, and, in 1967, he became the co-chair of the Cambridge Neighborhood Committee on Vietnam, whose members went door to door collecting signatures for a referendum opposing the war. In June, Israel launched a preëmptive strike against Egypt, setting off the Six-Day War, and proceeded to occupy the Sinai Peninsula, the Golan Heights, the West Bank, East Jerusalem, and the Gaza Strip. Many of Walzer’s anti-Vietnam allies opposed all of this, but he thought that Israel’s initial attack was justified; in his view, the country faced an imminent threat and needed to act. Seeking to explain why this was right, and why the war in Vietnam was not, he turned to the mostly Catholic tradition of just-war theory, and began work on what became his most famous book.
The book’s fundamental precepts are not complicated. It is just to defend your country from an invasion and it is unjust to invade a country that has not attacked you—although Walzer does allow for exceptions, mostly for humanitarian causes. It is just to assume certain risks to avoid civilian casualties and it is unjust to bomb towns indiscriminately to compel an enemy to surrender. The justice of going to war—what philosophers call jus ad bellum—is separate from jus in bello, the justice of how a war is fought. Soldiers on either side of a war have the same rights and the same obligations, regardless of which side is more broadly in the right.
Most of these precepts were already commonplace in international law, but they were often ignored in practice, and it was becoming conventional wisdom in some intellectual and political circles that war was a matter of naked self-interest. In this regard, many realists and pacifists were united: neither side believed that a war could be fought morally. In the book, Walzer draws on history as well as philosophy, quoting letters and memoirs from soldiers alongside speeches by politicians and by military leaders, illustrating how people attempt to fight in a moral fashion, and revealing that they usually make imperfect and uncomfortable decisions. Shortly after the book’s publication, a group of officers at West Point adopted it as a textbook, making it required reading for second-year cadets. It is still taught at military schools.
At the kitchen table, that May, we talked about the war in Ukraine, which was then a little more than a year old. It was, by Walzer’s lights, a morally straightforward war: Russia had invaded unjustly and Ukraine was defending itself. But war is never simple. “You know there’s now a version of just-war theory called jus ex bello?” he asked me. “Jus ex bello means ‘When is it just, or obligatory, to stop fighting.’ ” Just then his wife arrived, carrying shopping bags, and we paused to help put things away. Returning to the table, Walzer said that a legal scholar had recently used the jus ex bello doctrine in an op-ed to argue that the war had become so costly to Ukrainians that their government was now obliged to make concessions to stop the fighting. This was wrong, Walzer insisted—such a principle would encourage aggressors to be as destructive as possible.
In the months that followed, we exchanged e-mails and spoke over Zoom. Walzer wrote multiple pieces about the war in Ukraine, and I asked him about those writings as well as those from his past. That September, I drafted my article. On October 7th, Hamas attacked Israel and Israel retaliated. I asked Walzer for another interview. “Yes,” he replied. “We need to talk.”
We spoke again a few days later, over Zoom. Walzer wore thick glasses, and his hair was dishevelled; he offered a polite but fading smile. In the seventies, Walzer and his wife began making annual visits to Israel; by now, they had as many friends there as they did in the U.S. I asked him about an article he’d written years before titled “The Four Wars of Israel/Palestine.” He argued then that though some Israelis were justly defending their security within the country’s 1967 borders, others were unjustly fighting for a Greater Israel that included settlements and occupied territories. And though some Palestinians were justly fighting to end the occupation of the West Bank and Gaza and to create an independent state, others were waging an unjust war to destroy Israel altogether. Peace would only come, he wrote, when those fighting the just wars defeated those, on their own side, fighting the unjust ones.
Did he still see it this way? Yes, he said. And, unfortunately, he added, those fighting the just wars had not been running things on either side. Israel, he said, now had “to find a way to respond to the Hamas attack.” He went on, “It’s a principle of just-war theory that when there is a just cause, there has to be a way of responding.” Did the initial response by the Israeli government constitute a war crime? “I think a prolonged siege of Gaza, yes, is unjust,” he said. Judaism’s greatest philosopher would agree, he noted. “Maimonides wrote, memorably, one of my favorite sentences: ‘When one surrounds a city to lay siege to it, it is prohibited to surround it from four sides; only three sides are permissible.’ You have to allow civilians to leave. Well, Gaza is besieged on all sides.” Then he added, somewhat coldly, “It’s also stupid, because people will start dying, and it’s not Hamas that will be blamed for their deaths.”
I went to see him in person a few weeks later. It was Halloween and, in the streets, people were dressed as monsters and pumpkins. I found Walzer in the hall of his building, and we went up to his apartment together. He was moving more slowly than he had in May; he’d been experiencing back problems. At his door, I noticed a mezuzah. He has long been secular, and I asked him why he’d put it up. “So the antisemites know which door to knock on,” he said.
We took seats in a tiny corner of the apartment. A copy of the left-wing magazine Jacobin sat on a desk. Walzer looked less anxious than he had just after the attack, and he seemed sharper; I could tell that he’d discussed the subjects I was raising many times. “Every dead civilian is a human tragedy and a political asset for Hamas,” he said. “So, I assume, if there are any smart Israelis left, they are trying to minimize civilian casualties. But how committed they are to that I just don’t know.”
Walzer believed that Israel’s war was just but that the Army was waging it, at times, unjustly. Still, he rejected the idea of a ceasefire. If Israel accepted one, he said, “Hamas will claim victory and Israelis will live in fear.” He hoped that an Israeli victory would lead to the creation of two separate states, though he acknowledged that neither Hamas nor the Israeli government seemed to want this. Eventually, he said, there would be a different government in Israel, and he believed that there could be public pressure for such a solution. To my surprise, he was also open to the idea of a confederation, “which would be something less than sovereignty for each side.” When I noted that this was a development in his thinking, he said, “I just want to see some movement away from where we are.”
In 1988, Walzer wrote that terrorism might only be justified “if the oppression to which the terrorists claimed to be responding was genocidal in character.” I mentioned this idea in the context of Hamas’s attack. “That’s certainly not Hamas’s circumstance, because if they give up the project of annihilating Israel, and the border opens, investment comes in,” he said. “It may not be what they want, but the prospect of genocide isn’t there.” I noted that the most extreme members of Netanyahu’s Cabinet had been implying that erasing Gaza’s entire population was not out of the question. Walzer acknowledged that some people in the Israeli government “probably hope for something like that.” But the war cabinet included people with different views, he said. Perhaps there was a steadier hand on the Israeli response.
The following January, Walzer was scheduled to give a talk in Barcelona, near my home, to discuss “Thick and Thin,” which had now been published in Catalan. The book argues that our “thin” values of universalism and international solidarity grow out of the “thick” values that we learn in the communities we are born into; the thin values then help us to overcome the violence that can arise when we clash with other people’s thicknesses, so to speak. I was asked to be his interlocutor at the event, which was held in a four-hundred-seat basement hall beneath the historic Pati de les Dones at Barcelona’s Centre de Cultura Contemporània. Walzer’s back was still bothering him, and so he joined remotely, on a giant screen that loomed over the audience. It felt as though we were speaking in a bomb shelter.
Freedom and self-determination, Walzer said early on in the conversation, are universal values, and the task is to coexist with the differences they produce. Then, as if reading the room—which was packed with college students, progressive intellectuals, and the kind of engaged citizens who worry about the world and feel at home with someone who speaks in subordinate clauses—he interrupted himself, mid-reflection. “I have defended wars of humanitarian intervention because they are enforcing the universal value of life,” he said. “And I have opposed wars for regime change, which are motivated by some conception, some understanding of our own way of life, which we believe should be your way of life.”
The conversation continued for another half hour, drawing closer and closer to the war in Gaza until I asked him about it directly. Some things that seemed unjust, in his view, were not. Hamas, he said, had “a kind of military embeddedness in the civilian population” that “makes it virtually impossible to fight at all without killing civilians, and maybe even without killing large numbers of civilians.” Israeli officials had said that one-third of the Palestinian casualties were Hamas fighters, he noted. “If that’s true—if the ratio is two to one—given the crowdedness of Gaza and given the embeddedness of Hamas, I think that’s a respectable ratio,” he said. Some in the audience gasped. Then we took questions. A young man said he was offended by what Walzer had said about Gaza and that he would never read any of his books. Someone else asked him if the “thickness” of his Jewish upbringing thwarted his ability to see the “thin” injustice of the war. Walzer said he had been “a very strong opponent of some of Israel’s wars in the past,” but “not, as it turns out, of this one.”
There is a special difficulty in applying just-war theory to wars between a powerful military and an insurgent group. It’s a problem that “Just and Unjust Wars” does not address at length and that Walzer has thought about a great deal since. Two months after the event in Barcelona, he delivered a lecture on the topic at West Point, focussed on the war in Gaza. He has visited West Point multiple times since “Just and Unjust Wars” was published, and he said that the officers who taught there had told him that they “felt a special closeness with the IDF—the army, they said, most like ours.” In the lecture, he described the conflict as an “unprecedented” asymmetric war. “I don’t believe that there has ever been a war fought against an underground city,” he said, referring to the network of tunnels in Gaza. Hamas, he argued, had designed the fighting above ground “to produce civilian casualties.” The United States, he added, had sent Israel two-thousand-pound bombs, “not right for urban warfare,” to crush Hamas’s tunnels: “So we are complicit in the damage they did up above and in the civilian deaths they caused.” In May, he gave a longer version of the lecture, over Zoom, to the Minerva Center for Human Rights, in Jerusalem. There, Walzer noted that the powerful armies generally do most of the killing in these asymmetrical wars, but that such conflicts are also political matters, and that the more powerful side often loses. “The French in Algeria, the French lost,” he said. “The Americans in Vietnam and Afghanistan: we clearly lost. And in Iraq: we didn’t win. The Israelis in Lebanon and, a number of times before October 7th, in Gaza: too many cases of not winning.”
I asked Walzer about this the next time we spoke, over Zoom. If Hamas’s strategy had made it impossible for Israel to win the war without killing even more civilians than they already were—and if, in that case, Israel could not win the war at all, on account of public outrage and political pressure—wouldn’t the just thing be to stop fighting? Walzer told me that he had heard that argument from people on the Israeli left, and that, of course, it was important to prepare for negotiations and to hope for a diplomatic solution. But he regarded Israel’s situation as precarious. Israel could not have avoided this war, he said.
I thought of an article he had written years before, with the Israeli philosopher Avishai Margalit, titled “Israel: Civilians & Combatants” and published first in Haaretz and later in The New York Review of Books. “This is the guideline we advocate: Conduct your war in the presence of noncombatants on the other side with the same care as if your citizens were the noncombatants,” they wrote. Had Walzer changed his mind on this? No, he said. Then he posed a hypothetical involving a house partly occupied by Hamas, with rockets stored in the basement and civilians on other floors. “Let’s imagine the civilians in different floors were Israelis,” he said. What should Israel do about this? “I think that is the right way to ask the question,” he went on. “I am not sure what the answer is. I suspect the answer is, you bomb the apartment.”
That September, thousands of pagers and walkie-talkies, booby-trapped with explosives by Israeli operatives, were detonated in Lebanon and Syria, killing dozens, among them two children, and maiming or injuring thousands. Walzer wrote an essay for the Times calling the explosions “terrorist attacks” and “very likely war crimes.” The column constituted his harshest criticism of Israel to date, a fact he acknowledged the next time we spoke, a few months later. He had come to agree with the former Israeli Defense Minister Moshe Ya’alon, whose statements made him think of the conflict as two wars: a legitimate defense against Hamas’s attack and an unjust war of ethnic cleansing in northern Gaza. (The Israeli military denied Ya’alon’s accusation of ethnic cleansing, insisting that it acted “in accordance with international law.”) Walzer confessed, too, that he was beginning to wonder whether a war might be waged so wantonly that the justness of its cause is undermined. “I’ve always tried to keep those two judgments separate,” he said. “But I’ve been challenged by a number of people.”
It was January, 2025. The departing Biden Administration had brokered a ceasefire that allowed for the release of hostages taken by Hamas in exchange for Palestinian prisoners; the ceasefire held until March 18th, when Israel launched a surprise attack, with the approval of the Trump Administration, claiming that Hamas was not negotiating in good faith to release the remaining hostages. In one of the deadliest days of the war, the Israeli military killed more than four hundred people—mostly women and children, according to the Hamas-led Gaza Health Ministry. The next day, Israeli troops began a ground operation in territory that the Israeli Defense Forces had withdrawn from weeks earlier.
Walzer had just turned ninety years old. The Van Leer Jerusalem Institute and the Israel Academy of Sciences and Humanities organized a conference in his honor, to be held that June, and invited him to give a talk. He told me that he would speak about “Just and Unjust Wars” and the war in Gaza, but that he didn’t know what he would say. In May, Israel expanded its offensive in Gaza. In June, Israel bombed Iran, and Iran retaliated. The conference was postponed to the fall.
In October, I called Walzer again, and we discussed a so-called peace plan that had been announced by Trump, which included international administration for Gaza. Its terms were not far from Biden’s, but Walzer was not optimistic. Trump, he said, “wants to be seen signing an important document that he can wave in front of the Nobel Prize committee next year.” It was plain to him now that the Israeli government intended to occupy Gaza the way it has occupied the West Bank. “So I could say the war became unjust when it became clear that the end of the Israeli government was unjust,” he mused. Then he paused. “I don’t want to take that as a way out. I do think that the commitment to the siege was an act that was clearly unjust by in bello terms—and I think it required an opposition to the war itself, not just to the conduct of the war.” He offered a wry smile. “I’m not sure, at age ninety, that I’m going to rewrite the theory. But if I write on this issue, I’ll have to express that anxiety—that gross misconduct, war crimes, could reach a point where we are obligated to oppose the war itself.”
A month later, I flew to Israel to attend the conference. It was my first visit to the country since the war began. On the streets of Jerusalem I saw hip-looking young Israelis carrying assault rifles, some of them with military packs, presumably coming and going from their conscription duties. On the columns of train stations, stickers bore the smiling faces of soldiers in their twenties alongside motivational quotes and the dates of their births and deaths.
The evening of Walzer’s talk felt unusually warm. The lecture hall was packed; I took a seat in the back row. I’d spent the day listening to commentary on his work, much of it laudatory but some of it quite critical. The starkest assessment was delivered by Khaled Furani, a professor of anthropology, who called Walzer’s work a “lullaby” and a “chatty” narrative designed to soothe the Israeli conscience while masking the reality of Palestinian suffering. Furani deemed the current state of affairs a natural consequence of Zionist nationalism, and invited Walzer to flee the sinking ship of Zionism and board the ark of Islam and Palestinian liberation.
When Walzer took the stage, he affirmed his commitment to the safety of Israel and described his fury at the attacks of October 7th before turning to Israel’s conduct in the war. The recent raids in Gaza, he said, seemed intended to make it “uninhabitable, at least by its present inhabitants.” He added that “Israel had managed the siege in a way that meant, and seemed from far away intended to mean, that there would be no end to the suffering, no sustained relief, until a final, a total, victory, a victory that was never morally possible, probably not strategically possible, and that no one really believed in.” What’s more, “once there was a political way to defeat Hamas and to free the hostages, the war became unjust. The effort to win it, when there was no way to win without destroying Gaza and driving out all or most of its people” was, he said, a “criminal effort.”
The hall, by this point, was quiet. Walzer said that he did not trust the international reckoning regarding Israel’s actions that was sure to come. He wanted Israelis to do the reckoning themselves. “Please get it right,” he said.
The applause that followed was intense but sad. There were two more speakers: the Palestinian jurist and philosopher Raef Zreik, who argued that Walzer’s attempt to apply just-war theory to Israel and Palestine was rendered moot by his fundamental misreading of the founding of Israel, and a professor of American history named Yael Sternhell, who compared the situation of Palestinians in Israel to that of African Americans in the South after the Civil War. When they were finished, members of the audience went to where Walzer was sitting, surrounded by family, and offered congratulations. I joined them. He looked more curved by age than he had when I first interviewed him, two and a half years before; he held a cane. I asked if he was happy. That wasn’t the word, he said. Honored, rather. There had been some strong criticism of his work, I noted. Walzer smiled and gestured to a hearing aid. “I could not hear all of it, but I’ll read them,” he said. “Let us talk about it soon over Zoom.”
We spoke a week and a half later. Walzer responded thoughtfully to each of the critiques, but without backing down. He may change his mind on things, but he does so slowly, and, once he moves in one direction, he does not retreat.
This made his one notable shift during our nearly three years of conversation all the more striking: the wall between jus ad bellum and jus in bello, which had sustained his theory for almost half a century, was no longer sturdy. Walzer thought the matter through aloud with me, at one point letting out a small chuckle at his intellectual perplexity. A few minutes later, he looked down, leaning toward the screen and speaking with resignation. “There is a sense in which the carnage of Gaza, the ongoing carnage, simply made the war unjust,” he said. “Did the bombings of Hiroshima and Nagasaki? I thought they were violations of jus in bello, but you could say they made the war unjust. It went beyond a war crime. I don’t know how to explain it.”
I suggested an analogy with what, in his earlier work, he calls supreme emergencies: moments when you must do whatever it takes to preserve the “ongoingness” of your community. In those cases, your cause is so just that you are warranted to be immoral in protecting it. Perhaps, I said, on the other end of the spectrum, if your way of fighting surpasses the threshold of extreme carnage, the justice of your cause vanishes. “That sounds right to me. That sounds very good,” Walzer replied. “Most wars don’t reach anything like the carnage of Gaza,” he added. “Even the firebombings of German cities, which I thought was a war crime, I wonder—if it had gone on and on, if there had been five Dresdens, would that have made me think, No, this isn’t right anymore?”
We spoke again in June. The Trump Administration had launched military operations in both Venezuela and Iran and did not seem terribly bothered about demonstrating any kind of right to do so. “I don’t think our ‘Secretary of War,’ as he calls himself, is a believer in even the language of just-war theory,” Walzer said. The opposition to these operations was still often couched in such language, though—and the Vice-President, J. D. Vance, a convert to Catholicism, invoked just-war theory as a defense after the Pope criticized American warmongering. I asked Walzer if he thought that American foreign policy would ever be guided by such principles again, or if we lived in a permanently hardened world. “We’ll get a sense of that in November,” he said. “I hope this is a temporary aberration in American political history, but I can’t tell you that that’s what it is.”
On a more personal level, I was curious if the war in Gaza had changed Walzer’s relationship with the left—if it had altered his sense of where he belonged. He told me that he felt “radically alienated from Dissent,” his old magazine, but not only on account of Gaza; he also disagreed with its coverage of Ukraine and a “whole range of things,” he said. “The old Dissent always believed in the necessity of fighting on two fronts: against the authoritarian left and against the capitalist right, always,” he said. “And what’s happened with the American left right now is that they’re fighting only on one front.”
But for him the real conflict was not with others, he said. It was internal. He mentioned an old friend who had written to him, early in 2024, to tell him that he was pulling his punches, that he was not writing about Israel’s war in Gaza the way he had written about Vietnam. Was the friend right? “Well, look,” Walzer replied. “I wrote about Vietnam years after the war was over.” He had condemned the siege of Gaza from the first days of the war, but the bombing, for him, was different. Israeli friends had kept assuring him that the I.D.F. was choosing its targets carefully, he said. “Maybe I was late in concluding that that wasn’t entirely true—that there was a policy for parts of Gaza to be made uninhabitable,” he said. A moment later, he added, “I was certainly slow to see that.”
I heard regret in his reply, but also, I thought, still, self-assurance—a belief that he had done his best, whatever his faults, and that he had remained faithful to his underlying convictions, which had not changed. At one point, he reminded me that his critique of pacifism was formed when he was ten years old. I had asked Walzer, in an earlier conversation, what he hoped his legacy might be, now that he was ninety. He waited a long time before answering, and I got the sense that what he told me was what he would have said years, even decades, before, and that it was what he would say to me for as long as he was able. “I wanted to make it possible for people to talk about war in a way that would facilitate ending wars,” he said. “I wanted people to talk about politics in a way that would encourage egalitarianism. And I wanted to help, in the ways available to me, which were small ways, to make Jewish life more secure.” ♦