Ex Injuria and the Dualistic Axiom

[Lt Col R. Scott Adams is a US Air Force Judge Advocate. This article was written in his personal capacity and does not reflect any official position of the US Air Force or the US Government.]

Jus contra bellum is the raison d’être of modern international law. When that regulation becomes impotent, prescriptions of conduct within war, jus in bello, emerge to meet the purpose of the law. Jus ad bellum and jus in bello seek two complementary goals: First to prevent war; second to reduce suffering within it. It is, therefore, not surprising to find through unfortunate experience that where a state disregards one, a corresponding disregard of the other may be expected. 

This post seeks to discuss the relationship between jus ad bellum and jus in bello in a meaningful way for modern warfare. It joins recent scholarship in arguing that the orthodox approach of strictly dividing the casus belli from in bello conduct is not grounded in reality. An inflexible ad bellum-in bello dualism also creates an unintentional rejection of the principle ex injuria non oritur jus (A right cannot arise from an injustice). This issue is ripe for lex ferenda attempts to ensure the faithful application of in bello restrictions by unlawful aggressors, but the overall objective of this article is to advocate movement away from the strict ad bellum-in bello dichotomy toward a more meaningful embrace of ex injuria.  

Just War and Ex Injuria 

Long before the UN Charter prohibited the threat or use of force, theologians and philosophers sought to distinguish between just and unjust war.  Thomas Aquinas expressed the criteria for just war as: (1) sovereign authority; (2) just cause; and (3) righteous intention. Though rarely invoked in modern discourse, the US Department of Defense Law of War Manual refers to the “Just War Tradition” as a moral and philosophical foundation for the modern law of war.  For modern application, however, Professor Yoram Dinstein explained the just war tradition was abandoned because it was ineffective. Philosophical arguments made no historical impact on preventing war, and so the international community moved to adopt the jus contra bellum of the UN Charter. The Charter, according to Dinstein, has “wiped out” moral and philosophical tradition, in favor of a deontological view of positive law. All that matters is whether a use of force is consistent with the Charter. The juxtaposition between articles 2(4) and 51 of the Charter results in a construct where every armed conflict has at least one unlawful aggressor, and at least one lawful defender.

Using this construct soon after the Charter came into force, many argued that unlawful aggressors would not obtain any of “the rights usually associated with the conduct of war,” consistent with the principle of ex injuria. 

Ex injuria is the principle of law that prevents transgressors from benefiting from violations of international law. The principle is most commonly invoked in conjunction with the Stimson Doctrine, the policy of non-recognition of new states created by a war of aggression. Today, some scholars continue to argue that unlawful aggressors can never satisfy in bello requirements under ex injuria, but the majority view quickly abandoned this position for two pragmatic reasons: (1) Aggressors and victims both generally believe in the justice of its cause; and (2) this belief reduces belligerent’s motive to comply with the law. This intuitive and practical approach moved away from ex injuria, toward ad bellum-in bello dualism. 

The Dualistic Axiom

The ICTY’s Final Report to the Prosecutor stated that “the precise linkage between jus ad bellum and jus in bello is not completely resolved.” But after discussing conflicting views, the ICTY concluded “the most widely accepted and reputable legal” view was that ad bellum decisions were not relevant to in bello actions. The importance of maintaining a divide between ad bellum and in bello is now so well established, it has been called “an orthodox article of faith,” or “bedrock principle” of the law of war. Lawful defenders are bound by the same in bello restrictions as their aggressors; and the counter-intuitive reverse, belligerents with an unjust cause enjoy all in bello rights and privileges. This dichotomy is sometimes referred to as the dualistic axiom, 

The most authoritative codification of the dualistic axiom is found in the preamble to the First Additional Protocol to the Geneva Conventions (AP1). It states that compliance with AP1 does not “legitimize any act of aggression.”  The following paragraph confirms the reverse, stating AP1 “must be fully applied in all circumstances… without any adverse distinction based on the nature or origin of the armed conflict.”  

The United States has formally adopted the dualistic axiom, stating simply in the US Department of Defense Law of War Manual (Manual) that “jus in bello and jus ad bellum address different legal issues and should not be conflated.” In support of this conclusion, it first points to Common Article 1 of the Geneva Conventions (“ensure respect in all circumstances”) and then provides a list of policy arguments that support strict dualism. 

The Manual’s approach is an effective illustration of the prevailing view on ad bellum-in bello dualism. Advocates of dualism point to a broad principle of law and then emphasize extra-legal arguments to support it. This is a common approach because, as Professor Marko Milanovic stated, the dualistic axiom can only be supported “outside the law.”

In providing extra-legal justifications, the Manual argues that conflating ad bellum and in bello risks confusion. It points to the term “proportionality” having a different meaning in the two contexts. Second, conflation risks compromising the principles of sovereignty and humanity by subordinating one to the other. Third, conflation could lead to military forces questioning the lawfulness of their orders at every level. This, according to the Manual, could undermine good order and discipline. Finally, conflation could lead to individual belligerents receiving punishment for national decisions outside their control. 

In his book Just and Unjust Wars, Michael Walzer presents a philosophically framed argument for ad bellum-in bello dualism. For Walzer, the divide is essential to maintain the moral equality of belligerents. For jus in bello to survive, he argues, combatants must confront each other as moral equals, acting without blame under the direction of their political leaders. But he struggles to reconcile dualism with ex injuria: “Our judgments are doubled,” he says, “reflecting the dualist character of the theory of war” reveals an incoherence in the law of war. Walzer finds reconciliation in a division of responsibility. Political authorities hold responsibility for ad bellum; their subjects serve as combatants with in bello rights and obligations. 

Advocates of dualism are moved by honorable intentions. But the arguments are generally unpersuasive, or as described by scholars, “logically questionable” or “insufficient” to prevent overlap. The good order and discipline argument, for example, fails to convince because the concern applies equally to ad bellum and in bello decisions. Walzer’s argument is admirable but insufficient because it reflects an idealism detached from reality. Rudolph Dolzer artfully suggested in 2003 that “[t]he driving force behind military operations is end-oriented efficiency, not the pursuit of humanitarian considerations.” At the operational level of armed conflict there is a driving fixation on mission accomplishment, to the neglect of incidental or strategic concerns. Most commanders wish to avoid action that is clearly unlawful or immoral. But it is quixotic to believe those who plan or decide upon attacks today are animated by the moral equality of combatants. Perhaps this has always been true; perhaps modernity has aggravated the problem through distance and technology. But it may be one reason Professor Robert Sloane found, with disappointment, that “modernity has witnessed an erosion of the dualistic axiom,” or why Dolzer suggested the impotence of ad bellum has “spilled over into” in bello conduct. 

Nevertheless, the prevailing view is consistent with the US position: Ad bellum is not to be conflated with in bello. This dualistic axiom may be simplistically viewed as creating two distinct spheres of analysis under the law of war. Ad bellum is a legal Rubicon. Once crossed, in bello becomes the exclusive source of law, unaffected by what preceded it. Some scholars, such as Professor Robert Kolb, have argued that in seeking to ensure the full application of in bello, scholars have overstated the separation between ad bellum and in bello. In his view, they do not reside in distinct spheres; rather while ad bellum requires A, B, and C; in bello may simultaneously require X, Y, and Z. Sometimes they overlap; sometimes not. Others describe the ad bellum-in bello dichotomy as an “admixture,” like a spider web. 

But most scholars advocate for strict dualism and focus on two primary sources of problematic conflation: (1) The state survival loophole, ostensibly endorsed by the ICJ; and (2) mixing ad-bellum–in bello proportionality. A third, and perhaps more significant source of conflation may be added to this list in the form of what Sloane calls the “Aggressor-Defender Model.” 

Aggressor-Defender

Advocates of dualism acknowledge the casus belli affects the parties’ conduct in war, including their understanding of in bello obligations. As Dolzer stated, “no other segment of international rules depends for its acceptance so much on the circumstances and the climate of the moment.” Professor Michael Schmitt stated: “There is no basis for distinctions founded on legal or moral asymmetry, but the reality is that such differences, real or perceived, matter.”

Those differences matter immensely because, in practice, in bello obligations allow flexible readings of what constitutes permissible action. One effective example is found in a 2000 article by then-Colonel Charles Dunlap. The article followed soon after NATO operations in Kosovo, where NATO forces targeted electrical grids, oil refineries, and other civilian infrastructure. Dunlap does not directly address the dualistic axiom but argues it would be foolish to think jus in bello can be applied objectively without regard to the moral strength of each side. He dismisses the idea that we cannot identify which party to a conflict is the morally superior one. “We must not hesitate to demonize the demons” he argues. To do this, he does not advocate for a disregard of in bello principles, but rather for a broader understanding of what constitutes a military objective for the purpose of exercising moral authority against a “morally askew” civilian population. 

What Dunlap is implicitly advocating is not an exception to the dualistic axiom, but flexibility in its application, as influenced by the casus belli. But if we are to provide a more permissive in bello reading for the superior cause; we must, conversely, restrict a party to more limited in bello where the casus belli is insufficient. 

It will be extremely challenging to apply this principle, but there are two areas in which strict scrutiny of in bello decisions should apply to commanders of an unlawful aggressor: Distinction and proportionality.

Distinction

The principle of distinction is expressed in AP1, Article 48: Military operations may only be directed “against military objectives.” They define military objectives in Article 52(2) as those that (1) “make an effective contribution to military action” and (2) whose destruction “offers a definite military advantage.”  

The phrase “definite military advantage” prevents the targeting of objects that offer merely potential or indeterminate advantages. Although the principle of distinction is customary international law, some states view “war-sustaining objects” as meeting the distinction requirement. Michael Schmitt and many others have described this view as a “construct crafted by the United States” for practical flexibility. It is rejected by most states because it creates the potential to erode the principle so far as to become meaningless. This is why, historically, US officials took care to identify a strong nexus between economic objects and military operations. 

Under less careful leadership, the US position on war-sustaining objects is the toothpaste that cannot be returned to its tube. When those who plan or decide upon an attack are fixated on end-oriented outcomes, the war-sustaining justification gives license to total war on civilian infrastructure. Suddenly no argument is too weak, no effect too remote to establish an effective contribution to military action or a definite military advantage. When predicated upon ad bellum violations, an expansive interpretation of in bello distinction can result, in the abstract, in the dualistic axiom becoming the very antithesis of ex injuria non oritur jus. 

Proportionality

Proportionality is a topic that receives extensive attention in literature discussing ad bellum-in bello conflation. The prevailing view today is that combatants fighting for an unlawful aggressor can still prosecute targets consistent with the rule of proportionality where the “concrete and direct military advantage anticipated” remains detached from the casus belli. That may often be the case. Consider, for example, a lawful defender’s surface to air missile system (SAM) is targeted by an unlawful aggressor.  The tactical advantage of destroying the SAM can be considered in isolation and weighed against the expected incidental harm, cutting off the “slippery slope” that connects an attack to victory.

The contrary view points out that proportionality decisions are founded within a “moral dimension” that is trivialized by detaching military advantage from the casus belli. While this idea may not apply to every attack, it is true that some attacks hold an intrinsic nexus to the broader victory the aggressor seeks to achieve. Where the strategic objective is immoral, that immorality permeates every anticipated military advantage. Rather than denying this reality, we should acknowledge an inherent devaluation of military advantage under an aggressor’s proportionality calculation.

Application

Consider a hypothetical with both distinction and proportionality concerns, as described above. An unlawful aggressor is targeting what it has determined to be a series of military objectives that also serve as a critical economic resource for a defender state. One particular facility provides approximately more than half of the defender state’s export capability in that resource. The aggressor anticipates the military advantage is a substantial reduction in revenue to the defending armed force. The aggressor expects an unquantifiable amount of environmental harm, dozens of civilian deaths, and economic hardship on the entire civilian population. In considering the target, the dualistic axiom allows the aggressor to analyze the attack as an isolated event, divorced from its ad bellum act of aggression. The aggressor may hold up a war-sustaining argument to overcome the distinction hurdle. It will then conduct an in bello proportionality analysis that will be cloaked in uncertainty. The decision might not receive international endorsement, but it will likely be defensible under in bello isolation. It will also effectively accomplish the unlawful aggressor’s casus belli. 

Conclusion  

The dualistic axiom seeks to preserve humanitarian ideals but simultaneously defeats the principle of ex injuria.  This is why Walzer cautioned: “I am not sure whether the moral reality of war is wholly coherent.” Advocates for strict dualism will argue for alternative approaches to address the proportionality and distinction issues raised above. But our intuition tells us that the casus belli should matter. 

The dualistic axiom is not the fundamental cause of modern challenges to law of war compliance. But it certainly does not help. Strict dualism is not grounded in law and is not realistic or helpful. It should, therefore, be set aside and replaced by an understanding of an ad bellum-in bello dichotomy that is sufficiently flexible to uphold ex injuria, by holding unlawful aggressors to uncompromising in bello compliance.