Perhaps apocryphally, the Indian leader Mohandas Gandhi was once asked what he thought of Western Civilization. He supposedly replied, “I think that would be a good idea.” This exchange more or less summarizes my view on war and justice―a just war would be a good idea, but I have not seen it yet. Admittedly, I am a realist and am therefore deeply skeptical about the just war tradition in general and its application to policy in particular. I believe this for two simple reasons. First, war can never be made truly just. Second, it is not clear what the unintended consequences would be of trying to enact a “just” war. To believe otherwise is naïve, ahistorical, and dangerous.

Because of my views, Paul D. Miller’s new book is one of the best things I have ever read about just war theory―and I still do not like it very much. Indeed, of the thirty or so books I have read on the topic, it ranks third after classic tomes by St. Augustine and St. Aquinas. However, this may be closer to damming it with faint praise than raising it to exalted status.

Miller’s work does many things well. It is very clearly written and organized, transparent about its biases, exhaustively researched and cited, humble about its limitations, and truly original. As a piece of scholarship, it is remarkable from start to finish, and rightfully deserves serious intellectual engagement within the just war and international law fields.

At its core, Miller’s book tries to answer two basic questions: “when is war just?” and “what does justice require?” To address these fundamental issues, the book dedicates approximately two-thirds of its page count to chronicling the evolution of thinking on just war over time. He identifies three competing traditions, which he calls Augustinian, Westphalian, and Liberal, and does an excellent job of critiquing their evolution over time and their theoretical and practical limitations. In the remaining chapters of the work, Miller continues to impress by providing his own theory of just war, which he titles Augustinian Liberalism. As the name implies, this is a combination of what he believes are the best elements of the first and third traditions in his intellectual history. In his proposed theory, the goal of the international community is to establish and maintain ordered liberty. By Miller’s own admission, this is no simple task as it requires fighting wars to remove threats to the international order and committing to protracted peacekeeping and reconstruction efforts to ensure that this order endures.

In the context of jus ad bellum, wars can and should be fought to end tyranny and oppression and to (re)establish order. This is a more interventionist version of liberalism’s theory of responsibility to protect, which Miller believes does not go far enough to protect the lives of vulnerable peoples. In terms of jus post bellum, this argument makes a much more expansive claim about the duties and responsibilities that victorious powers have after the fighting stops. According to this argument, post-war justice must be a part of every phase of the war from its initial conception and planning, to its conduct, to its termination, and ultimately to the rebuilding of a just society that is consistent with the goals of ordered liberty.

After building his new theory, Miller then subjects them to a series of test cases from recent history. Here, he finds much to critique about each of these cases and provides some interesting commentaries about how policymakers should have done better. For example, in contrast to much of the commentary on the 2003 invasion of Iraq, Miller argues that this was defensible on jus ad bellum grounds, claiming that it was fought with the generally good intentions of freeing oppressed peoples and promoting ordered liberty. Despite his support for the invasion of Iraq, he is much more critical of the US peacekeeping, counterinsurgency, and reconstruction missions on jus post bellum grounds. Here, he is clearly bitter about the way in which the Iraq war ended, claiming that it made the region worse not better, and thus the US’s exit was deeply immoral.

In a similar manner, Miller argues that continued US engagement in Afghanistan is necessary to build a lasting peace. While this point has been overcome by events, he makes the impassioned argument that the war was never a priority and was perpetually starved for resources. Here, Miller is critical of Presidents Bush, Obama, and Trump and argues that they all failed to understand the importance of the mission from both the perspective of the fight against terrorism, but also in the context of the just war tradition.

Reading Miller’s tragic lines about the moral obligation to Afghanistan in the days immediately after US forces departed the country is heartbreaking, but it actually made me remember why I am so wary about the just war tradition. The sad fact is that wars almost always fail to achieve their goals or live up to the lofty expectations of just war theorists for the very reasons I highlighted in the opening of this review―the fundamental immorality of war and the power of unintended consequences.

While Miller’s work suggests that the tragedies in Iraq and Afghanistan could have been avoided through a better understanding of justice and a stronger commitment to post-conflict reconstruction, I cannot agree with this assertion. By its own terms, Miller’s more ambitious vision of justice, particularly jus post bellum, makes it more difficult and less likely to achieve than before. But this misses the point. The failures in these wars were not caused by a lack of understanding of the just war tradition, an absence of good intentions, or even a lack of effort. The sad fact is that they were never going to satisfy the requirements of the just war tradition, no matter how smart we were, how Godly we tried to be, or how much blood and treasure were wasted.

I believe that war cannot be made just and that to think otherwise is a dangerous fantasy. To this end, I take a fundamentally Clausewitzian approach to war. War tends towards extremes. War brings out enmity and passions from the people and their governments. War aims are rarely transparent and frequently shift. War is a deeply imperfect means for achieving policy objectives. War is about killing people and breaking things. War cannot be fully understood or rationalized, let alone made just.

Even assuming that this fundamental issue could be resolved, I believe the power of unintended consequences makes it almost impossible to retain clarity of purpose and purity of intention over time. To again return to Clausewitz, there is a fundamental difference between war on paper and war in reality. War is neither waged in a vacuum nor at a fixed time and place. It is waged by, in, and among the people. Their passions and emotions are fickle, irrational, and contradictory. Mistakes happen. People and equipment break. Small and unnoticed factors multiply and spiral out of control. Minds change. Elections have consequences. Friction is omnipresent. Over time, it truly becomes impossible to reign in or control the complex and uncontrollable phenomenon that is war.

As such, Miller’s work strikes me as honest and well-intended, but ultimately naïve and dangerous as it suggests that war can be made just and that it can be controlled. While I believe that political theorists should try to impact the world around them, I am deeply pessimistic about their ability to achieve their desired ends. Complex and contingent arguments such as this one are easy to misunderstand, reduce to one-liners for policymakers, or used to justify decisions that have already been made.

This argument can be unintentionally dangerous because it makes a moral argument for the use of force which is almost certain to be misunderstood and abused. As a soldier, practitioner, and scholar, Paul Miller knows that war is wicked, as well as the truism that even well-intentioned ideas can lead to unintended ends. As such, I have no reason to question his objectives or moral compass. What I worry about is that less prudent, less academically honest, and less conscience-stricken people will use and abuse his work for their own self-serving ends.

While I am no pacifist, I know enough of war to understand that even “good” and “just” conflicts are premised on lies and misperception, fought with animalistic rage, enable atrocities such as rape and murder, and rarely provide a lasting and peaceful order. This does not mean that we should not try to “stir the better angels of our nature,” and conduct ourselves as morally as possible. Nor does it mean that wars of self-defense and last resort should not be fought with the goal of winning decisive victories. However, we should also never believe that war can be made better either. War is a profoundly imperfect, inefficient, and iniquitous element of the human experience. It corrupts everything it touches, even those with pure intentions.

Despite my strong disagreements, I applaud Paul D. Miller for his excellent book and genuinely hope that he is right and I am wrong. He offers an impassioned, ambitious, and well-reasoned case for justice and, “I think that would be a good idea.”