Michael Walzer's Just and Unjust Wars is one of those books that leaves the reader with more questions than answers, and that is precisely its value. It is not a study of tactics, campaigns, or military history, instead it examines the moral dimensions of warfare and asks military professionals to confront an uncomfortable reality: success in war is not measured solely by outcomes, but also by the choices made along the way. In a profession centred on the organised application of violence, Walzer challenges us to consider not only what can be done, but what should be done.

What struck me most was the book's insistence that war does not exist outside morality. There can be a tendency to view conflict as a domain where necessity overrides other considerations and where difficult circumstances excuse difficult actions. Walzer rejects this entirely, arguing that moral judgement remains relevant, particularly when the stakes are highest. For military professionals, this is a confronting proposition because it removes the comfort of believing that difficult decisions can be reduced to technical or procedural calculations. Rather; judgement, character, and responsibility remain central.

For both study and professional development, I have worked through the book a number of times, and I found myself reflecting less on warfare as an abstract concept and more on the individuals required to wage it. Walzer repeatedly returns to themes of honour, integrity, courage, and restraint. He acknowledges the brutal realities of conflict, yet never accepts brutality as justification in its own right – a trap that many fall into. The result is a nuanced examination of the tensions that sit at the heart of military service. The same profession that requires individuals to close with and defeat an enemy also demands discipline, restraint, and accountability. The same battlefield that rewards aggression also punishes recklessness. The same circumstances that produce acts of extraordinary bravery can reveal fear, weakness, and ethical drift or compromise.

One of the book's greatest offerings is its recognition that ethical considerations are not separate from military effectiveness: that they are inextricably a part of it. Tactical decisions have moral consequences, just as moral decisions often have tactical consequences. The challenge for soldiers and officers is not simply to understand doctrine, capability, and planning processes, but to appreciate the human effects of military action. Just and Unjust Wars reinforces that military professionalism involves balancing competing responsibilities rather than blindly pursuing a single objective. The book also encouraged me to think differently about the relationship between military necessity and moral obligation. In the Army, we rightly place significant emphasis on mission achievement, placing it before multiple other considerations. Just and Unjust Wars does not dispute the importance of achieving objectives, but does argue that the manner in which objectives are achieved matters. This is particularly relevant in a contemporary operating environment; technology may have transformed the character of war, but the need for ethical judgement remains unchanged.

However, not every argument in the book is entirely convincing when viewed from a practitioner’s lens. At times, Walzer appears to seek certainty in situations that are inherently ambiguous. The battlefield rarely presents clean ethical choices and there are occasions where the boundaries between right and wrong become difficult to identify in practice. Yet even where I found myself questioning his assertions, I found value in the exercise. The book will force a reader to critically examine assumptions they may otherwise accept without challenge; in the future where officers and soldiers will be faced with options of the least bad choice this is a critical mental skill.

I recommend Just and Unjust Wars to anyone serving in the Army, but particularly those moving into positions of greater responsibility. It is not merely an examination of Jus ad Bellum and Jus in Bello, it is much more than that. Junior leaders will gain an appreciation of the ethical dimensions of command, while senior leaders will recognise many of the enduring tensions between mission, risk, and responsibility. Ultimately, Just and Unjust Wars serves as a reminder that the profession of arms is not simply about fighting effectively. Rather, that it also must include exercising force responsibly. In a profession where the consequences of decisions can carry strategic, human and ethical weight, that remains as relevant today as when the book was first published.