By Lara Kajs
As military confrontation escalates between the United States, Israel, and Iran, questions about strategy and geopolitics dominate public debate. Yet the conflict also raises a deeper issue: whether the legal framework governing the use of force in international relations is being quietly set aside.
When nations go to war, the first casualty is often the truth—but the second is frequently the law. Watching the United States and Israel launch a widening military campaign against Iran, I find myself returning not only to the geopolitical questions surrounding the conflict, but also to its legal implications. International law was designed precisely for moments like this, when the impulse to use force collides with the rules meant to restrain it.
The United States and Israel are now engaged in a widening military campaign against Iran—one that is already reshaping the geopolitical landscape of the Middle East. Airstrikes have targeted missile facilities, military bases, and infrastructure across several Iranian provinces. Yet reports have also emerged that hospitals and schools have been struck during the bombing campaign—sites that occupy a particularly sensitive place within the framework of international humanitarian law.
At stake is not only the outcome of a regional confrontation, but the credibility of the legal system designed to regulate when states may resort to war. These developments raise a fundamental question that extends far beyond the battlefield: under what legal authority was this war launched?
War Without Authorization
The central legal issue is not simply the scale of the military campaign, but whether the use of force itself was authorized under international law. Since the end of the Second World War, the international system has imposed strict limits on when states may lawfully resort to armed force.
Conflicts rarely begin with a single decision. More often, they emerge gradually as diplomatic frameworks weaken, legal constraints erode, and political tensions accumulate over time. The current confrontation between the United States, Israel, and Iran reflects precisely this pattern.
The question, therefore, is whether the present conflict falls within the narrow circumstances in which international law permits the use of military force.
The Legal Limits on the Use of Force
Under the framework established by the United Nations Charter, the use of force between states is broadly prohibited except in two narrow circumstances. A country may act in self-defense if it has been subjected to an armed attack, or military action may be authorized collectively through the United Nations Security Council when international peace and security are deemed to be threatened.
In the present conflict, neither condition appears clearly satisfied. No formal Security Council authorization has been issued permitting the United States or Israel to undertake military operations against Iran. In fact, the Council has remained divided on the issue, reflecting the geopolitical tensions that often paralyze collective action within the body.
This leaves the justification of self-defense as the principal legal argument advanced by the states involved in the campaign. Yet the legal standard for self-defense under international law is not a vague political concept but a narrowly defined doctrine requiring the presence of an actual or imminent armed attack.
The absence of clear evidence that Iran launched a direct armed assault immediately preceding the strikes has therefore raised significant questions among legal scholars about whether the self-defense justification can withstand scrutiny.
The Legacy of the Nuclear Deal
The legal and diplomatic context of the conflict is also shaped by the earlier collapse of the Joint Comprehensive Plan of Action (JCPOA), the multilateral agreement negotiated during the administration of Barack Obama.
The agreement once placed strict limits on Iran’s nuclear program under international monitoring by the International Atomic Energy Agency. For several years, inspectors reported that Iran was largely complying with the deal’s provisions.
When the United States withdrew from the agreement in 2018 under President Donald Trump, the diplomatic framework that had governed the nuclear dispute began to erode. Iran subsequently reduced its own compliance with certain aspects of the agreement, while tensions between Washington and Tehran intensified.
The collapse of that diplomatic structure did not automatically create a legal basis for war. International law does not permit states to initiate military action simply because negotiations have failed or because an adversary is viewed as a long-term security threat.
Civilian Targets and the Risk of War Crimes
Equally troubling are reports that the air campaign has struck hospitals and schools—locations that occupy a protected status under the principles of international humanitarian law.
The laws governing armed conflict, including the Geneva Conventions, establish clear rules intended to limit the suffering caused by war. Central among these rules is the principle of distinction, which requires belligerents to differentiate between military targets and civilian objects.
Hospitals, schools, and other civilian facilities are therefore afforded special protection during armed conflict. These protections are not absolute. If such facilities are used for military purposes—for example, as a weapons depot, command center, or launching site—they may lose their protected status.
Even in those circumstances, attacking forces remain bound by the principles of proportionality and precaution. Military commanders must determine that a target offers a definite military advantage and that any anticipated civilian harm would not be excessive in relation to that advantage.
If civilian infrastructure has indeed been struck without a clear military justification, the attacks could raise serious concerns under international humanitarian law. Allegations of unlawful strikes against protected sites often trigger international scrutiny and may fall within the jurisdiction of investigative bodies such as the International Criminal Court.
When hospitals, schools, or other civilian facilities are repeatedly damaged during military operations, questions about compliance with humanitarian law tend to become central to the broader political and legal debate surrounding the conflict itself.
These concerns about the conduct of hostilities intersect with an even deeper legal question: whether the war itself was lawful under the international system governing the use of force.
The Problem of Unprovoked War
At its core, the legal controversy surrounding the current conflict rests on whether the war itself was justified under the international system that emerged after the Second World War—a system designed specifically to limit the circumstances under which states may resort to armed force.
Without either Security Council authorization or a demonstrable act of self-defense, military action risks being viewed as an unlawful use of force under the principles of international law.
Such a determination carries significant legal and political consequences. Violations of the prohibition on aggressive war undermine the legal architecture intended to regulate international conflict, making future disputes more difficult to contain within diplomatic channels.
Law in the Age of Power Politics
The war now unfolding between the United States, Israel, and Iran illustrates the enduring tension between geopolitical power and legal restraint. International law provides a framework designed to regulate the conduct of states, but its effectiveness ultimately depends on the willingness of those states to abide by its limits.
When powerful nations act outside those constraints, the rules themselves begin to erode.
Whether the current conflict will ultimately be judged as lawful self-defense or as an unlawful act of aggression remains a matter of intense debate among scholars, diplomats, and policymakers. But the legal question cannot simply be brushed aside in the fog of war. The prohibition on aggressive war—enshrined in the United Nations Charter after the devastation of the twentieth century – was meant to ensure that military force would become the last resort of states, not the first.
If wars can be launched without clear provocation, without authorization from the United Nations Security Council, and without adherence to the protections embedded in the Geneva Conventions, then the guardrails designed to limit human suffering begin to collapse.” — Lara Kajs
If wars can be launched without clear provocation, without authorization from the United Nations Security Council, and without adherence to the protections embedded in the Geneva Conventions, then the guardrails designed to limit human suffering begin to collapse.
And when those guardrails disappear, civilians—those in hospitals, schools, and homes far from the battlefield – are the ones who ultimately pay the price.
Moments like this test whether international law is merely aspirational rhetoric—or a framework that powerful nations are willing to respect even when it constrains their strategic ambitions. The answer will shape not only the future of this war, but the credibility of the legal order meant to prevent the next one.
Anticipatory Self-Defense and the Question of Imminence
Supporters of the current military campaign may point to a more expansive interpretation of self-defense known as anticipatory self-defense. Under this doctrine, a state may claim the right to use force before an attack occurs if the threat of that attack is considered imminent and unavoidable. Although the concept has been debated for more than a century, it remains controversial within the framework of international law and is not explicitly codified in the United Nations Charter.
The classic formulation of anticipatory self-defense emerged from the nineteenth-century Caroline Affair, which established that any pre-emptive use of force must be justified by a necessity that is “instant, overwhelming, and leaving no choice of means, and no moment for deliberation.” Modern legal scholars frequently return to this standard when evaluating whether anticipatory self-defense can be lawfully invoked.
In the case of the current conflict, the absence of clear evidence of an imminent Iranian attack raises serious doubts about whether that threshold has been met. Without such immediacy, the legal justification for preventive military action becomes increasingly difficult to sustain under prevailing interpretations of international law.
The Stakes for the International Legal Order
Beyond the immediate humanitarian consequences, the conflict carries implications for the stability of the international legal system itself. Since the end of the Second World War, the prohibition on the use of force contained in the United Nations Charter has served as one of the central pillars of the global order. By limiting when states may lawfully resort to armed conflict, the Charter sought to replace the era of unilateral warfare with a system governed—at least in principle—by collective security and legal restraint.
When major military powers bypass those constraints, the consequences extend far beyond the immediate crisis. Other states may feel justified in adopting similarly expansive interpretations of self-defense or preventive war. Over time, this dynamic risks weakening the normative force of international law, transforming rules intended to restrain violence into flexible tools shaped by geopolitical power.
For that reason, debates over the legality of the current conflict are not simply academic exercises. They are part of a larger struggle over whether the international legal framework created in the twentieth century can still meaningfully regulate the use of force in the twenty-first.
Published 10 March 2026
Photo Credit: Attack on residential homes in Tehran on 3 March 2026 by Hossein Zohrevand. Licensed under CC By 4.0 International.
Lara Kajs is the founder and executive director of The Genocide Report, a Washington, DC-based educational nonprofit focused on atrocity prevention and international law. She is the author of several field-based books on conflict, displacement, humanitarian crises, and international humanitarian law, drawing on extensive research and field experience in Yemen, Syria, and Afghanistan. Her writing and public speaking focus on atrocity crimes, forced displacement, the protection of civilians, and the legal frameworks governing armed conflict.