The Military Intervention in Iran |
The debate in the West over military intervention in Iran is often reduced to a seemingly simple question: Is it permitted under international law? The traditional interpretation of the United Nations Charter suggests that the use of force is generally allowed only in self-defense against an armed attack by another state and, in other circumstances, requires authorization from the UN Security Council. On paper, this framework appears straightforward, but it is increasingly difficult to reconcile with contemporary geopolitical realities. The Charter presupposes a functioning system of collective security in which states report measures of self-defense to the Security Council, which then acts effectively to restore international peace and security. In practice, however, this mechanism is structurally constrained in a multipolar international order, where veto powers frequently paralyze decision-making. Against this background, the narrow, legalistic approach reflects a model of conflict that no longer corresponds to the realities of modern warfare, making the question of legal justification for intervention far more complex than the traditional framework suggests.
The conflict involving Israel, the United States, and the Islamic Republic of Iran was not initiated by Israel or the United States in 2026; rather, it reflects decades of hostilities in which Iran has pursued its strategic objectives through proxy forces and other means. Only now have Israel and the United States formally invoked their right to self-defense in response to direct and indirect attacks linked to Iran and its affiliates. Those who argue that the current use of force is illegal often overlook nearly five decades of actions by Iran and its proxies and rely on an overly rigid and narrow interpretation of international law.
Examples of major incidents associated with Iranian support or direction include the 1979 US Embassy hostage crisis in Tehran; the 1983 Beirut barracks bombings; the 1984 US Embassy annex bombing in Beirut; the Lebanon hostage crisis (1982–1992); repeated missile and rocket attacks on US and coalition forces in Iraq and Syria during the 2000s and 2010s; the 1996 Khobar Towers bombing in Saudi Arabia; the 1992 bombing of the Israeli Embassy in Buenos Aires; and the 1994 bombing of the AMIA Jewish community center in Buenos Aires, among others.
Against this historical background, the question arises whether the right of self-defense must be confined to interstate conflicts under an unduly restrictive reading of international law or whether such a reading constitutes a misinterpretation of the law.
The Scope of Self-Defense
Historically, the UN Charter, and the right of self-defense it encompasses, were formulated in the context of the Second World War, when states needed a legitimate mechanism to defend themselves against the aggression of other states. However, a literal and rigid reading of the text falls short of its spirit and purpose. This is evident from legal developments showing that international law must adapt to the geopolitical realities of each era to remain relevant. The following discussion illustrates this point.
First, it is widely recognized that the right of self-defense is not limited to states alone but can also extend to non-state actors whose actions are attributable to a sponsoring state. While the International Court of Justice (ICJ), in Military and Paramilitary Activities in and against Nicaragua (Nicaragua v. United States, ICJ 1986), required that a state exercise “effective control” over the specific operation in which the wrongful acts occurred to establish state responsibility, the International Criminal Tribunal for the former Yugoslavia (ICTY), in Prosecutor v. Tadić (Appeals Chamber, 1999), rejected this strict test as too narrow for determining whether an armed conflict is international in character. The Appeals Chamber reasoned that requiring control over each specific operation is ill-suited to the realities of armed conflict: a state may organize, coordinate, or plan the activities of an armed group without directing every operation, yet still exercise sufficient overall control to render the conflict international. Hence, the ICJ’s “effective control” test applies specifically to state responsibility for internationally wrongful acts but is less suitable for the general classification of conflicts.
This is precisely the evolutionary legal approach that must be adopted to address the challenges of a changing world in general, and the hostilities between the Islamic Republic of Iran and its proxies against Israel in particular. A rigid, standardized interpretation of international legal principles presupposes classical interstate warfare and does not adequately capture the structure of contemporary proxy conflicts. Non-state armed groups, such as Hamas and Hezbollah, operate through complex networks of financing, training, and logistical support provided by Iran, deliberately structured to fall short of the classical threshold of direct control. This exposes the limits of a rigid doctrinal framework when applied to hybrid and indirect forms of warfare. By contrast, an evolving interpretation, as described above, better accommodates the realities of contemporary realpolitik. In this light, attacks by the Islamic Republic of Iran and its proxies that are attributable to the regime and that have caused civilian harm in Israel and the United States as well as the Arab Gulf countries, in principle, trigger the inherent right of self-defense under international law.
Moreover, state practice and the development of United Nations Security Council resolutions demonstrate a gradual shift away from a rigid legal framework and its traditional interpretation. In the aftermath of the attacks of September 11, 2001, the Council explicitly recognized that the right of self-defense may be exercised in response to attacks by non-state actors. For example, Resolution 1368 (2001) “recognizes the inherent right of individual or collective self-defense.” This development reflects an evolution in the understanding of what constitutes an “armed attack,” extending it beyond strictly interstate uses of force and enabling the exercise of self-defense against non-state actors, including terrorist organizations affiliated with the Islamic Republic of Iran. The atrocities committed by these groups and their sponsoring state justify the exercise of the inherent right of self-defense.
The Conditions of customary international law
One of the main objections raised by opponents of the current war is that the threat posed by Iran and its proxies was not imminent, which is traditionally one of the three conditions required for invoking the right of self-defense. The classic interpretation of imminence asserts that “the necessity of self-defense is instant, overwhelming, leaving no choice of means, and no moment for deliberation.” However, this formulation, originating from the Caroline case (1837), does not reflect the realities of the contemporary world.
In modern contexts characterized by continuous, long-term patterns of violence carried out through proxy actors, the concept of imminence can no longer be confined to a strictly immediate temporal threshold. Rather, it must be understood in light of sustained attacks and credible, openly declared intentions. Where armed groups engage in repeated attacks over extended periods, and where their support by a state is substantial and persistent, the condition of “imminence” for invoking self-defense can reasonably be considered to have been met under a more realistic interpretation of the right of self-defense.
The other conditions of necessity and proportionality, as required by customary international law, are also satisfied. Decades of diplomacy have failed to prevent or repel the attacks, and the current use of force is directed solely at military targets that pose a threat.
The Constrains and Risks of the Legal Mechanism
The procedural requirement under the UN Charter that measures taken in self-defense be reported to the Security Council increasingly appears disconnected from institutional reality. The Charter provides that such measures “shall be immediately reported to the Security Council,” yet the persistent inability of the Council to act effectively raises doubts about the practical significance of this obligation. This structural paralysis is clearly illustrated by the ongoing war in Ukraine, where repeated recourse to the Security Council has not produced effective collective action due to the veto power of its permanent members. In such a context, the reporting requirement risks becoming a purely formal exercise devoid of substantive consequence. In a system where enforcement is structurally blocked, reliance on procedural omissions as a basis for declaring a use of force unlawful risks becoming formalistic and selectively applied.
Putting this reality into perspective requires moving beyond the question of legality. In times of crisis, the distinction between legality and legitimacy becomes decisive for effective and timely action. Over recent decades, legal scholarship has increasingly addressed the concept of humanitarian intervention in situations where multilateral mechanisms fail. This approach does not deny the importance of the Charter framework but recognizes that, in exceptional circumstances involving large-scale and systematic violations of fundamental rights, strict adherence to institutional procedures may be insufficient to protect civilian populations. This perspective becomes particularly salient when considering events such as the reported mass repression of protesters in Iran, where, within less than 48 hours, large numbers of civilians were subjected to lethal force, including targeted shootings, as well as violence in medical settings against both patients and health care providers. Such patterns of banal evil correspond to the type of systematic violence against civilians that has informed discussions on humanitarian intervention.
Especially when diplomatic and economic measures have been seriously attempted and have failed, when the primary objective of an intervention is the protection of the civilian population rather than geopolitical gain, and when there is a reasonable prospect that such intervention will effectively halt or mitigate the violence – particularly at the request of the affected population – a strict reliance on the institutional model of 1945 is insufficient to address situations of acute and large-scale human rights violations. Deviation from this model may compromise strict legality but satisfies the requirement of legitimacy.
Legality versus Legitimacy
The tension between legality and legitimacy is not unique to international law. It was addressed explicitly in postwar German jurisprudence, particularly in the criminal proceedings against former border guards of the German Democratic Republic, commonly referred to in scholarship as the Mauerschützenprozesse (“border-shooter trials”), decided by the Bundesgerichtshof (BGH) in the 1990s. In these rulings, the BGH rejected the defense that the guards had acted lawfully simply because they were complying with the positive law of the GDR. Drawing on the legal philosophy of Gustav Radbruch, the court held that where the contradiction between statutory law and justice reaches an intolerable level, the statute must yield; extreme injustice deprives a legal norm of its validity. In essence, the court determined that domestic rules permitting the intentional killing of unarmed civilians could not retain legal effect, even if formally enacted, thereby rejecting rigid adherence to doctrines such as Gesetz ist Gesetz (“a law is a law”) in circumstances of gross injustice.
Transposed to the international plane, this reasoning underscores that a purely formalistic reading of international law – detached from evolving realities and from the imperative to protect fundamental human rights – risks producing outcomes that are legally defensible yet normatively untenable. Where institutional mechanisms fail, where sustained violence against civilians persists, and where affected populations themselves call for protection – as is the case with the people of Iran – legitimacy may operate as a necessary corrective to rigid legality.
Accordingly, even where a military intervention does not fully align with the institutional framework established in 1945, it may still find grounding in evolving interpretations of self-defense, in state practice as reflected in Security Council resolutions, and in broader principles of justice recognized in both international and domestic legal traditions. From this perspective, an approach that entirely separates legality from legitimacy risks reducing law to a formalistic construct devoid of substantive moral authority.