When States go to war to replace an enemy’s very system of government, the goals of the military campaign can lead to noncompliance with the rules that regulate belligerents during armed conflict. The end result threatens not only international law prohibiting the resort to war except under very specific circumstances, but also international humanitarian law that protects civilians in wartime.
Experts writing on these pages, and elsewhere, have almost unanimously declared the recent uses of force by the United States in Venezuela and by the United States and Israel in Iran to be violations of international law. Some, such as Oona Hathaway, have noted, correctly, that States increasingly violate the prohibition of the use of force, or excuse such violations by other States. Some scholars condemn these violations and call for accountability. Others, such as Yuval Shany and Amichai Cohen, as well as Ken Watkin, argue for relaxation of the rules to better reflect States’ perceived security interests, but they fail to offer a convincing roadmap for doing so without creating a permission structure for exactly what the law is meant to accomplish: the prohibition of naked acts of aggression, such as those committed by Russia in Ukraine (a response to Shany and Cohen from Rebecca Hamilton and Tom Dannenbaum can be found here). Meanwhile, little has been said about the effect of the illegality of the resort to force on compliance with the rules for conduct of the armed conflicts triggered thereby.
Violations of Jus ad Bellum are Not the End of International Law…
As introduced above, experts are debating whether we have reached the end of international law.
To my view, the declaration of the death of international law is, to paraphrase Mark Twain (and echo Watkin), exaggerated. International law is a broad, deep and complex compilation of elements, too numerous to parse here. Suffice it to say that although many of us (including the undersigned) have observed that the Jus ad Bellum (the law on when States can resort to military force) is at the core of the “rules-based international order” (RBIO), it would be hyperbole to suggest that challenges to the prohibition of the use of force herald the end of that norm, let alone the disintegration of the larger RBIO. States have too much skin in the game, developed over too much time, to abandon the entire project, from rules relating to diplomacy, to trade and finance, to health, to environment and natural resource exploitation, to the high seas and outer space, to human rights and cooperation on criminal enforcement, among other realms. That said, increased disrespect for the Jus ad Bellum will certainly create pressures on the sustainability of these, and other aspects of international law.
…But They Do Put IHL at Great Risk
If there is one aspect of international law that is most at risk due to degradation of the Jus ad Bellum, it is the Jus in Bello, or International Humanitarian Law (IHL), referred to by some as the Law of Armed Conflict (LOAC). Jus ad Bellum may be understood as the law addressing the “why” of using force, and Jus in Bello, or IHL, as the law addressing the “how.”
IHL is codified in the Geneva Conventions and various so-called Hague Conventions. The Geneva Conventions concern protections accorded those “hors de combat” (outside of combat) such as injured combatants, prisoners of war, and civilians. Hague Law consists of various conventions governing the conduct of hostilities, or the means and methods of combat.
International law envisions a strict dichotomy between Jus ad Bellum and Jus in Bello. This separation, often called a “firewall,” is designed to ensure that the rules of war apply equally to all parties to armed conflict, regardless of whether their cause is just or their invasion illegal. The reasons for the principle of equality of parties to conflict under IHL are simple. First, there is no real-time referee to authoritatively distinguish aggression from self-defense and to enforce the consequences of that distinction. Second, parties to armed conflict could not be expected to obey IHL rules if they applied asymmetrically on the basis of a Jus ad Bellum analysis, and civilians would become the ultimate victims.
…Especially When Regime Change is On the Menu
Regime change is widely considered in general a violation of Jus ad Bellum norms because it directly targets a state’s political independence and is likely a disproportionate use of force. Outside of specific Security Council mandates, unilateral regime change is “highly disfavored” and carries a “heavy burden of justification.” When a war is initiated with an illegal or “total” goal, it sets a dangerous precedent for the conduct that follows, and the theoretical firewall between Jus ad Bellum and Jus in Bello undergoes severe structural strain. The pursuit of a total political outcome – the dismantling of a sovereign government – often leads to the erosion of the core pillars of IHL: the principles of distinction, proportionality, and precaution.
The Principle of Distinction
The rule of distinction under IHL requires parties to differentiate between combatants and civilians, and between military objectives and civilian objects. In a regime-change conflict, the definition of a “military objective” often expands. Attackers may target “dual-use” infrastructure such as electrical grids, State media, or civilian government ministries, arguing that these are essential to the regime’s survival and therefore must be destroyed. But under IHL, targeting dual-use objects is not so clear-cut; they are not recognized as a separate legal class of targetable objects, but rather, a commander should (in theory) establish that any particular target, including one that is used for both military and civilian purposes, does in fact qualify as a military object under the specific circumstances at hand (although approaches to targeting dual-use objects are complicated and somewhat varied, as highlighted in this discussion), and then apply a proportionality test to all civilian aspects of the object if it is properly deemed a legitimate target. In a regime change operation, we can predict that the answers to those sensitive questions would shift in the direction of attacks that come with unacceptable loss of civilian infrastructure and lives.
The slippage of fundamental IHL norms in the context of regime change is also applicable to the targeting of civilians themselves. As seen in recent reports on Operation Epic Fury, strikes have targeted political leaders and members of the security and intelligence services responsible for domestic repression. Some of these, like the IRGC, an official component of Iran’s armed forces, may be targetable as combatants. Others, like Senior Intelligence Ministry (MOIS) official Mohammed Baseri, are civilian government officials. Obviously, these elements of the regime’s “grip” must be loosened, if not destroyed, to effect regime change, and yet, such individuals are likely not ipso facto combatants nor civilians directly participating in hostilities – the only categories of persons subject to targeting under IHL. Accordingly, war for the purpose of regime change necessarily creates a strong incentive to expand targeting beyond the permissible confines of IHL.
The Proportionality Paradox
The rule of proportionality prohibits attacks expected to cause incidental civilian harm that is “excessive in relation to the concrete and direct military advantage anticipated.”
The determination of how much civilian harm is proportionate, and therefore, permitted, will vary depending on whether the military objective is tactical (“take that hill”) or strategic (“change that regime”). Strategic Proportionality applied to this context would seem to take the position that when the goal is regime change, the “military advantage” of a single strike is at risk of inflation; if a commander believes a strike on a civilian building, let’s say with some military objective included, will “destabilize the regime,” they may justify high collateral damage as a “necessary cost” for a transformative political outcome, and consequently non-excessive to the high-value military advantage anticipated. Scholars have noted that a reinvigorated analysis of proportionality is necessary because commanders often weigh “long-term” benefits (which could be political, like the formation a new government), against “immediate” civilian deaths. In short, armed conflict undertaken for the purpose of regime change risks facilitating proportionality assessments that stretch the appropriate bounds of the proportionality principle.
The Duty of Precaution
The principle of precaution requires States to “take all feasible precautions” to minimize civilian harm.
In regime-change scenarios, the “speed” of the advance often overrides the “feasibility” of precautions. The desire to “paralyze the chain of command” can lead to rapid-fire targeting that skips the rigorous intelligence vetting required to ensure civilians are not in the blast zone of a high-value target. If the goal is the “total defeat” of a system, there is less incentive to take costly or time-consuming precautions that might allow regime leaders to escape or regroup. Again, a fundamental norm of IHL finds itself potentially bowing and breaking in the context of regime-change operations.
Behavioral Feedback Loop: A Race to the Bottom
The pursuit of regime change also creates a perverse incentive for the defender. When a regime faces an existential threat or a demand of “unconditional surrender,” as demanded of Iran by U.S. President Donald Trump, it has little incentive to follow IHL.
A cornered regime is, for example, more likely to use human shields, embed military assets in hospitals, or deploy prohibited weapons as a last resort. This, in turn, provokes the attacker into unlawful reprisals and more indiscriminate strikes, creating a downward spiral of respect for IHL. Even the International Court of Justice has not been unsympathetic to extreme measures that are difficult to square with accepted notions of proportionality, when taken in the service of State preservation. A plurality of the Court, for example, could not conclude that even the use of nuclear weapons would be definitively unlawful in the event that the survival of the State (though not the regime) is at stake.
In the context of the U.S.-Israeli Operation Epic Fury, this issue has come to the forefront as we see Iran (the cornered regime) targeting both technology companies and banks in Israel, with Iran claiming that they are in part responding to U.S./Israeli targeting of banks in Tehran. These are violations of IHL’s principle of distinction under which mere “war sustaining activities,” as distinct from acts constituting “direct participation in hostilities” are not targetable, according to the majority view of experts. Were it otherwise, every taxpayer in a State at war would be a target. Of course, IHL has traditionally recognized a right of reprisal, conduct that would normally be illegal but is considered lawful when committed by one State in response to, and in an effort to discourage, a prior illegal act by an adversary. However, reprisal is never permitted against non-combatants. These circumstances exemplify both the perverse incentives regarding the principle of distinction for the would-be regime changers, and a real-world “race to the bottom.”
The “Illegal but Legitimate” Trap: The False Promise of Humanitarian Intervention
Even where the goal is not explicitly regime change, IHL principles come under severe pressure where intervention is justified as humanitarian (a goal often associated with regime change). Recent analysis explores the reawakening of the “illegal but legitimate” doctrine. This framework, resting on a justification of “moral legitimacy,” often leads to a breakdown in legal restraint, as the attacker views their cause as so righteous that the specific rules of IHL become secondary to the “larger good” of the regime’s removal.
For example, during the 1999 Kosovo War, NATO conducted a 78-day bombing campaign against Serbian forces – not in self-defense and not authorized by the Security Council, and therefore, unlawful. The stated purpose of the campaign was humanitarian, in response to mass atrocities committed against the Kosovar civilian population by Serb forces. The campaign largely utilized high-altitude airstrikes, often around 30,000 feet, to destroy military infrastructure while avoiding anti-aircraft defenses. Strikes targeted strategic installations, power plants, bridges, and command centers in Kosovo and Serbia, including in Belgrade. The high-altitude bombing was deemed responsible for significant civilian damage and casualties, with estimates of around two thousand civilians killed, often due to the inability to distinguish military objectives from civilian objects at that altitude. In a post-conflict analysis by the Prosecutor of the International Tribunal for the Former Yugoslavia, (see the full report here), which raised the question of whether NATO was justified in conducting a “zero casualty war” – an argument arose that the metrics normally applied to the rules of distinction, proportionality, and precaution should be relaxed, as NATO’s involvement was purely humanitarian, thus NATO forces should not have to face the same risks as other parties to the conflict. The NATO bombing did force Serbian forces to end their ethnic cleansing campaign. The Serbian regime fell over one year after the bombing campaign and the ICTY declined to further investigate the NATO bombing campaign.
The NATO bombing in Kosovo is not, however, the most significant example of legally unsupported Jus ad Bellum rationales resulting in IHL harms. After all, it stopped the Serb atrocities. A greater harm to both civilians and to the integrity of the legal structure is when false humanitarian justification is used to rationalize acts of aggression.
Conclusion
The relationship between regime change and IHL is one of inherent tension. By pursuing a “total” political goal that lacks a clear legal basis under Jus ad Bellum, States create a battlefield environment where the standard rules of distinction, proportionality, and precaution are viewed as obstacles to victory rather than essential constraints. To preserve the humanitarian mission of IHL, the international community must resist the “sliding scale” where the perceived justice of a cause is used to excuse injustices of conduct.
