Just and Unjust Uses of Limited Force. Daniel Brunstetter. Oxford, UK: Oxford University Press, 2021.

Just and Unjust Uses of Limited Force by Daniel Brunstetter offers an insightful look into the permissions and limits of international force short of war. Brunstetter proposes a theory of justice for limited force (or vim in Latin). The need for such a study is indicated by the fact that most of the terminology used to describe morality in war does not adequately capture contemporary uses of force, which warrants additional vocabulary. This is what Brunstetter provides. Full of contemporary examples and counterfactuals, Brunstetter's work offers a relevant heuristic to aid in understanding the fights of today. Yet, despite the book’s emphasis on moral theory, the insights are often more strategic than strictly moral.

The book progresses in three phases. The first presents the limits of the two primary paradigms used to justify and limit force—the law enforcement paradigm and the just war paradigm. Brunstetter argues the law enforcement paradigm is not the default alternative to war. Such a clean delineation does not account for the problems inherent in areas where order is fractured or contested. He notes that there are circumstances in which the effectiveness of the law enforcement paradigm breaks down because it is too restrictive. Conversely, using warlike measures is too permissive because it blurs the lines between peace and war. There are similar problems within the just war paradigm because limited force, so common these days, exists on the margins of war. Hence, Brunstetter identifies the undertheorized gaps in the just war paradigm.

Constructing the language to describe the justice of limited force, thereby filling the gaps, is the aim of the second part. Brunstetter appeals to the various categories of contemporary just war thought to structure his argument—the justice of limited force (jus ad vim), justice in limited force (jus in vi), and justice after limited force (jus post vim).

To understand the justice of using limited force as well as justice in the execution of limited force, Brunstetter contends, requires a clear idea of what can be accomplished by using limited force.[1] That is, the desired post-vim world must first be imagined. Such a vision is constrained, though, by the nature of limited force, which aims at what Brunstetter calls “morally truncated victory.”[2] As opposed to the often more total aims of war, limited force aims are just that—limited. To ensure the aims remain within the bounds of vim, he posits three principles. The re-establishment principle holds that limited force should aim at a minimalist view of order such that a return to the law enforcement paradigm is feasible.[3] Additionally, because limited force often entails some form of punishment, he proposes the containment principle, which holds that aims of limited force should be to contain evil rather than topple it.[4] Finally, he contends that post-vim vision should pursue conciliation, which assists belligerents with overcoming grievances and establishing more enduring peace and justice.[5]

This introduces a new principle—the probability of escalation. Escalation, here, is not a process of incrementally increasing, tit-for-tat interactions, but a line that is crossed from limited force to war.

With this ideal post-vim world in mind, it is possible, then, to consider the ability of limited force to achieve that vision. This opens the door to the jus ad vim, or justice of limited force, discussion. Brunstetter emphasizes the importance of the moral independence of limited force from war, writing “we should not be thinking ‘let’s try limited force first, and, if that fails, then we can go to war.’”[6] The purpose of limited force is not to anticipate war, but to avoid “crossing the Rubicon” and committing to the uncertainty and harms of war.[7] Brunstetter writes, “Only scenarios when there is relatively small chance that vim acts could lead to war can be justified.”[8]

This introduces a new principle—the probability of escalation. Escalation, here, is not a process of incrementally increasing, tit-for-tat interactions, but a line that is crossed from limited force to war. Brunstetter proposes that this is a moral principle because war introduces “totalizing and unpredictable consequences” that ought to be avoided.[9] He helpfully offers also that the principle not only has a restraining element(avoid escalation) it also has a warranting element (prevent the escalation of atrocities, WMD proliferation, or local conflict into regional conflict).

Brunstetter accepts that sometimes, when force is the necessary means to achieve legitimate aims, civilian casualties may occur.

When considering the justice of individual acts of limited force—or jus in vi—there is a predisposition toward maximal restraint.[10] In contrast to the jus in bello sphere of principles from just war that permits targeting all combatants once war has begun, the jus in vi principles only permit harming those who are active threats or are necessary targets to achieve the post-vim aims. Maximal restraint means not attacking those who might otherwise be liable, but it does not mean abiding by the overly restrictive norms of the law enforcement paradigm.[11] That is to say that Brunstetter accepts that sometimes, when force is the necessary means to achieve legitimate aims, civilian casualties may occur. But he argues that vim scenarios permit greater opportunity to achieve a “zero-tolerance” collateral damage standard.[12]

The final phase of the book revisits jus post vim from a different perspective than assumed earlier. The previous consideration was to set aims and to consider what the ideal outcomes would look like. This phase looks at post-vim in the non-ideal context of when “limited force fails to achieve the jus post vim ideals.”[13] Brunstetter notes that we can consider vim to have failed if there is an unjust escalation to war, if containment is not achieved, or if a minimum degree of order is not established.[14] However, this does not mean that we are left either to escalate to war or to suffer evil and disorder. It means that we have recourse to a “secondary” set of principles—the punishment principles.[15] The first he calls “the escalation management principle.”[16] When containing evil fails, a state may perhaps use vim in the form of punishment and call for limited punitive force to continually keep it in check. The second punishment principle is “the demonstrative retribution principle.”[17] This principle applies when it is necessary to provide a punitive response to misbehavior to “teach” the target entity that their actions will be punished. Brunstetter remains adamant, though, that states must remain conscious of escalation risks and remain committed to maximal restraint even in such non-ideal post-vim worlds.

To escalate, even to a just war, it seems, would be immoral, unless that war is to prevent mass humanitarian catastrophe.

Brunstetter’s overall project is a laudable effort at theorizing uses of force short of war. The book successfully notes  a variety of relevant considerations within the space such as the varieties of forms of limited force, different escalatory scenarios, and some of the general concerns of using force outside of the context of war. However, there is a particular theoretical challenge that must be overcome to envision the space of vim in the same way Brunstetter does.

Brunstetter “privileges a presumption against war at the heart of just war thinking.”[18] This perspective, while not unique, carries great weight in his theory. For instance, one of the two keystones of vim is a presumption against escalation.[19] He also insists that the measure of the moral worth of vim aims and actions are their risk of escalation to war. To escalate, even to a just war, it seems, would be immoral, unless that war is to prevent mass humanitarian catastrophe.[20] What reasons does he offer, then, for his readers to accept such a presumption?

What the book loses in its moral appeal, it gains in strategic and practical appeal.

There are two discernible functions for the presumption within the work itself. The first is to sustain the theoretical foundations of vim, which should be conceived of as “an alternative set of options” to war.[21] Making a presumption against war, then, preserves vim as a distinct category within which theorizing may be done. If the reader fails to buy-in to the assumption, though, the entire basis for the subsequent theory falls flat. The second function is pragmatic in character, to avoid making the shift to the “wide and unpredictable destruction” of war.[22] Brunstetter characterizes this function, though, in moral terms stating that we have a “moral penchant” against such unpredictability and destruction. However, this seems to deny, or at least fails to consider, the possibility of justice and moral restraint within war itself, by suggesting that restraint exists only in the context of vim. Indeed, Brunstetter overtly claims as much, calling escalation the opposite of restraint.[23] Such a view, though, is at odds with the tradition he relies on to construct his theory, because restraint and limitation are the aims of just war reasoning.[24] What then are the implications for the reader who does not make this fundamental assumption?

For such a reader, what the book loses in its moral appeal, it gains in strategic and practical appeal. For, while it may not be morally necessary to avoid escalation, it is often practically desirable. The practical insights Brunstetter offers, particularly regarding the characteristics of limited force and types of escalation, are helpful constructs for reasoning about military options and risks short of war.[25] For instance, he notes how vim permits appeal to a broader array of causes than war, but it also necessitates much more limited effects.[26] If the practical desire is to avoid escalation, then policy makers must make sure they maintain clarity in their stated causes and tight limits on the effects they seek. In this way, Brunstetter offers practical insights and ways to reason about force short of war, even if we do not accept his initial presumption against war.

Just and Unjust uses of Limited Force fits comfortably into the ever-expanding genre of philosophical literature that seeks to bring new categories of thought to just war, usually with unique Latin terminology and principles.[27] Those drawn to this field will have a natural interest in Brunstetter’s work. Moreover, even those who are not interested in just war, per se, but in practical reasoning about force short of war, can also benefit from this book as Brunstetter offers helpful practical analysis of the topic, as noted above. In sum, Brunstetter offers an insightful analysis of force short of war, even for those who do not accept his initial presumptions. There does not seem to be any decline in potential opportunities for limited uses of force on the horizon, making this work, and its wide distribution, all the more important.

Paul Vicars is an Air War College Fellow and Ph.D. student at Baylor University. The views expressed are the author’s alone and do not reflect those of the U.S. Air Force, the Department of Defense, or the U.S. Government.

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Notes:

[1] Daniel R. Brunstetter, Just and Unjust Use of Limited Force: A Moral Argument with Contemporary Illustrations (New York: Oxford University Press, 2021), 90.

[2] Brunstetter, Just and Unjust Use of Limited Force, 92–96.

[3] Brunstetter, Just and Unjust Use of Limited Force, 98–102.

[4] Brunstetter, Just and Unjust Use of Limited Force, 110–13.

[5] Brunstetter, Just and Unjust Use of Limited Force, 120–24.

[6] Brunstetter, Just and Unjust Use of Limited Force, 130.

[7] Brunstetter, Just and Unjust Use of Limited Force, 139–42.

[8] Brunstetter, Just and Unjust Use of Limited Force, 131.

[9] Brunstetter, Just and Unjust Use of Limited Force, 166.

[10] Brunstetter, Just and Unjust Use of Limited Force, 200.

[11] Brunstetter, JJust and Unjust Use of Limited Force, 223–31.

[12] Brunstetter, Just and Unjust Use of Limited Force, 230.

[13] Brunstetter, Just and Unjust Use of Limited Force, 235.

[14] Brunstetter, Just and Unjust Use of Limited Force, 236–39.

[15] Brunstetter, Just and Unjust Use of Limited Force, 242–52.

[16] Brunstetter, Just and Unjust Use of Limited Force, 248–49.

[17] Brunstetter, Just and Unjust Use of Limited Force, 249–52.

[18] Brunstetter, Just and Unjust Use of Limited Force, 26.

[19] Brunstetter, Just and Unjust Use of Limited Force, 17.

[20] Brunstetter, Just and Unjust Use of Limited Force, 24 and 193–98.

[21] Brunstetter, Just and Unjust Use of Limited Force, 139.

[22] Brunstetter, Just and Unjust Use of Limited Force, 24 (see also 140 and 141).

[23] Brunstetter, JJust and Unjust Use of Limited Force, 14.

[24] See James Turner Johnson, Ideology, Reason, and the Limitation of War: Religious and Secular Concepts 1200-1740 (Princeton, NJ: Princeton University Press, 1975); and James Turner Johnson, Just War Tradition and the Restraint of War (Princeton, N.J.: Princeton University Press, 1981).

[25] Brunstetter, Just and Unjust Use of Limited Force, 173–93.

[26] Brunstetter, Just and Unjust Use of Limited Force, 130.

[27] Other such works include, Daniel R. Brunstetter and Jean-Vincent Holeindre, eds., The Ethics of War and Peace Revisited: Moral Challenges in an Era of Contested and Fragmented Sovereignty (Washington, DC: Georgetown University Press, 2018); James M. Dubik, Just War Reconsidered: Strategy, Ethics, and Theory, Battles and Campaigns (Lexington, Kentucky: University Press of Kentucky, 2016); Caron E. Gentry and Amy Eckert, The Future of Just War: New Critical Essays, Studies in Security and International Affairs (Athens, Georgia: University of Georgia Press, 2014); Eric Patterson, Ethics beyond War’s End (Washington, DC: Georgetown University Press, 2012).