This interview with Nigel Biggar—Emeritus Regius Professor of Moral and Pastoral Theology at the University of Oxford and an Anglican priest—was conducted in the aftermath of the twelve-day war between Iran and Israel, at a moment when questions of war, restraint, legality, and moral justification had once again forced themselves into global public consciousness. Experiencing war’s proximity not as an abstract geopolitical event but as a lived political and ethical condition prompted a renewed inquiry into the moral grammar through which war is justified, condemned, or normalized.
Against this background, the conversation explores the enduring relevance—and contested limits—of just war theory in contemporary conflicts, where civilian harm, legal ambiguity, and strategic escalation blur the line between necessity and excess. Drawing on Biggar’s long-standing engagement with moral realism, international law, and political responsibility, the interview probes moral uncertainty in decision-making, the doctrine of double effect, humanitarian intervention, and the tension between ethical judgment and legal constraint.
Rather than treating war as a purely legal problem or a tragic inevitability, the discussion situates it at the intersection of ethics, politics, and lived experience—asking whether moral reasoning can still meaningfully constrain violence in a fractured international order, and whether refusing to judge, in the name of skepticism or pacifism, risks becoming its own form of complicity. This interview is offered not as a defense of war, but as a philosophical attempt to think responsibly within its shadow.
With this in mind, JURIST contributor AmirAli Maleki—having witnessed the twelve-day war between Iran and Israel firsthand—approached Nigel Biggar to raise the philosophical questions that emerged from that experience.
AmirAli Maleki: Given war’s inherent unpredictability—civilian casualties, long-term trauma, political instability—how can we ever have sufficient moral certainty to justify initiating it? Doesn’t this uncertainty make “just war” reasoning dangerously permissive?
Professor Nigel Biggar: Since we are creatures and not gods, certainty is a commodity in very short supply in human affairs. ‘Just war’ reasoning—or any ethics of war—constrains and limits war by subjecting it to criteria of justice. Apart from absolute pacifism, the alternative is war that is absolutely unconstrained. So, yes, ‘just war’ reasoning is relatively permissive, but it is still more constrained than its non-pacifist alternative.
The absolute pacifist view is that war is so destructive and uncontrollable that it can never be morally justified and that ‘peace’, however unjust, is always preferable. That is a view that commands some good reason, I think. However, I don’t accept it for two reasons.
The first is that ‘peace’ is quite as morally complicated and ambiguous as war. In 1994, Britons, Americans, and the French didn’t go to war in Africa. They stayed at peace, which was good for them. But it wasn’t so good for the Tutsi, since it left the Hutu at peace to slaughter 800,000 of them in the Rwandan genocide.
The second reason why I cannot adopt the position of a principled pacifist is that injustice and oppression that proceeds uncurbed tends to grow in extent and depth. For example, if Vladimir Putin had provoked military opposition from the US and the UK, when he intervened in Syria in 2011, he would have been discouraged from seizing Crimea in 2014. If he had provoked military opposition in 2014, he would have been discouraged from invading the rest of Ukraine in 2022. If he had provoked more resolute and whole-hearted military opposition from the US and Europe in 2022, he would have been discouraged from prosecuting an atrocious war for over three years and pursuing ‘grey zone’ warfare against NATO members, thereby flirting with the apocalyptic possibility of all-out nuclear war. In brief, more war earlier would have meant less war later.
Maleki: Is the doctrine of double effect—distinguishing intended harms from merely foreseen ones—genuinely robust enough to apply to modern warfare, where the line between intention and foreseeable consequence is often blurred or impossible to verify?
Biggar: If we don’t distinguish intended harms from unintended but foreseen harms, we render the successful prosecution of war impossible. That would be desirable, of course, for pacifists, but not for those of us who think that some kinds of injustice should not be tolerated. As I have argued elsewhere, if we judge only by foreseen harms, the Allied invasion of Italy in 1943-44 and Normandy in 1944 would be considered immoral, with the consequence that the genocidally racist Nazi Empire would have survived, perhaps expanded, or at the very least been prolonged.
I don’t know quite what’s meant by being ‘genuinely robust enough’. I infer that you mean that the difficulty of determining intentionality implies that relying on it makes us unable to reach judgments in a timely manner. We have to wait until we can scrutinize the moral and legal decision-making of military commanders. I think that that is true and just has to be accepted.
That said, there is circumstantial evidence that indicates what the intention of a military act is. For example, if military forces take care to deploy the most accurate and least destructive weapons available when targeting a military objective—or if they warn civilians of an impending strike—that does indicate that killing civilians is not what they intend.
Maleki: You argue that soldiers can act out of justice, love, or compassion rather than hatred. But doesn’t this risk sanitizing violence—enabling self-deception in which individuals or states claim noble intentions while committing cruelty?
Biggar: In my book, In Defence of War, I present empirical and historical evidence that supports my claim that commanders in the field and combat soldiers can act out of love of various kinds, which constrains their use of violence. This justifies that use, but it doesn’t sanitise it. I have always been clear that war is a dreadfully destructive state of affairs, which, for that reason, should be avoided at much cost, although not at all costs. And since war is always conducted by sinners, not saints, it will almost inevitably involve elements of injustice. Nonetheless, like any large-scale human endeavour, a war can still be justified overall and all things considered, notwithstanding those elements.
Maleki: If states may override international law on moral grounds—as you suggest in certain cases of humanitarian intervention—what safeguards prevent powerful states from abusing this license to justify arbitrary or self-interested interventionism?
Biggar: There are no guarantees against abuse, but there can be safeguards. To a large extent, international law just is what the majority of states find acceptable or not. Therefore, it was significant that NATO’s intervention in Kosovo in 1999, undertaken to stop the ethnic cleansing of Muslim Kosovars and regional destabilization, involved forty states, including Greece and Turkey, who are customarily at loggerheads. Contrary to what some on the British left asserted, it was not a case of the US flexing its unilateral muscles just to demonstrate its power. According to the eminent Finnish diplomat and international law jurist, Martti Koskenniemi, the majority of lawyers regarded NATO’s action as unlawful (according to the letter of the UN Charter), but nonetheless morally legitimate. In brief, the intervention attracted widespread retrospective international approval. So, the safeguards against the cynical breaking of international law are the diplomatic costs—the loss of a law-abiding reputation and international trust and consequently diminished cooperation and fewer alliances.
Maleki: When assessing historical wars and deeming some of them “just,” how do you address the fact that hindsight is partial, evidence contested, and motivations often mixed? Can retrospective moral judgment ever truly validate a war’s justice?
Biggar: Very few wars are uncontroversial. For example, while an overwhelming majority of Anglo-Saxons regard the war against the Nazis in 1939-45 as morally justified, some have argued and still do argue that Britain should not have prosecuted the war after the fall of France in 1940 but instead should have come to terms with Hitler. All one can do is to mount as cogent a moral argument as one can, expose it to critical testing, strive to persuade in its favour, and hope that most people will recognize its merits.
There is a distinction to be made between whether the original decision-makers deserve blame for going to war and whether, in retrospect, such belligerency was morally justified. One might judge, in retrospect and all things considered, that certain belligerency was unjustified and yet exonerate the original decision-makers from blame, since factors that render what they did morally wrong, they could not have known. In other words, while their belligerency was in fact unjustified, they had acted in good faith and cannot be blamed for what they did.
As for a mixture of motivations, that characterizes much human action. Unlike quasi-Kantian idealists, I don’t believe that self-interest necessarily corrupts an otherwise moral action. Some national self-interests—say, the security of a national population—are perfectly legitimate. Not all self-interest is selfish. That said, sometimes the motivational mixture does contain selfish as well as moral elements. An action so motivated can still be morally justified, if the moral element predominates and is not subverted by the immoral one.
Maleki: The criteria of “just cause,” “last resort,” and “grave injustice” all rely on interpretation. Who has the authority to decide when injustice is grave enough or when peaceful means have been exhausted—and how do we prevent states from lowering these thresholds to suit their purposes?
Biggar: Unfortunately, the only elements of ‘just war’ thinking that have been formally incorporated into international law are the principles that govern the conduct of war—discrimination and proportionality—not those that govern the decision whether or not to go to war in the first place. Whereas in ‘just war’ thinking ‘just cause’ is fundamentally the defence of the innocent against a grave injustice, according to post-1945 international law ‘just cause’ is primarily national self-defence. Therefore, if one is going to make an ethical—as distinct from a legal—judgement about going to war, one cannot depend on the utterances of bodies of international lawyers.
The ultimate responsibility for making decisions about war must rest with national governments. For it is up to them to decide whether or not to abide by the letter of international law, as laid down by the UN Charter. There is no global government with its own armed forces; the UN only possesses such military force as states lend it. In the end, the use of military force rests with states, each of which must decide for itself. How far the decision-making of a state is informed by ethical principles such as those of the ‘just war’ tradition will depend on how far those principles are present in the bloodstream of public discourse, not least that of the press.
Maleki: Your account relies on moral-ontological realism—a moral order independent of human opinion—to ground just war theory. In a pluralistic world with conflicting moral frameworks, what grants ethicists the legitimacy to declare a war morally justified when those subjected to it may reject their metaphysical assumptions?
Biggar: If there is no universal moral order independent of human opinion, there really is no morality and there are no rights; there are merely human conventions.
All individuals have a duty to act and speak according to their consciences—that is, according to their grasp of what the moral order requires of them. Individual ethicists have a duty to contribute to public deliberation by using their talent for ethical analysis to speak the moral truth as they see it. Sometimes, what individuals think and say is unpopular and attracts widespread criticism and hostility. Nonetheless, they might still be right and public opinion wrong. No one who adheres to an Abrahamic faith—whether Judaism, Christianity, or Islam—can disagree with such a view. After all, that is what defines a prophet.
Editor’s note:
Nigel Biggar is Emeritus Regius Professor of Moral and Pastoral Theology at the University of Oxford and an Anglican priest. He is the founder and former director of the McDonald Centre for Theology, Ethics, and Public Life, and is widely known for his work on just war theory, political ethics, and the moral evaluation of violence. His publications include In Defence of War (2013), What’s Wrong with Rights? (2020), and Colonialism: A Moral Reckoning (2023).
AmirAli Maleki is a philosophy researcher and the Editor of PraxisPublication.com. He works in the fields of political philosophy, Islamic philosophy, and hermeneutics.
