Israel and the United States began major military operations against Iran on Feb. 28. In response, Hezbollah began launching drones, rockets, and missiles into Israel on March 2. Israel responded in turn with a large-scale air and ground campaign into Lebanon that has killed hundreds of people, including dozens of children, several medics, and at least one priest, while displacing hundreds of thousands of civilians from their homes.
The European Union’s High Representative for Foreign Affairs and Security Policy says that “Israel has the right to self-defence in line with international law” but that “Israel’s response has been heavy-handed,” causing “mass displacement,” and risking “severe humanitarian consequences.” She concludes that “Israel should cease its operations in Lebanon.” This statement suggests that Israel’s response exceeds the limits of proportionality internal to the right of self-defense because of the cumulative harm it is inflicting on civilians (see here). This article argues that Israel’s response exceeds the limits of necessity internal to the right of self-defense because Israel has a reasonable alternative. The requirements of proportionality and necessity are complementary, and Israel’s military campaign in Lebanon appears to exceed both.
This article primarily concerns the legality of Israel’s military campaign in Lebanon under the United Nations Charter. But it helps to start with Iran. As an earlier article explained, Israel’s ongoing use of force against Iran is a manifest violation of the United Nations Charter because it is neither authorized by the United Nations Security Council nor an exercise of Israel’s right of self-defense in response to an unlawful armed attack (whether actual or imminent) by Iran. It is simply an unlawful act of aggression. Iran’s response has included strikes directed at Israel’s civilian population which both violate international humanitarian law and exceed the limits internal to self-defense. But these unlawful acts by Iran do not permit Israel to use force against Iran in self-defense. The right of self-defense permits the use of force in response to an unlawful armed attack only when necessary and only to the extent proportionate. The use of defensive force is necessary only if nonforcible alternatives are unavailable or have no reasonable prospect of success (see here). There is no necessity for Israel to use force against Iran in self-defense because Israel has a nonforcible alternative with a reasonable prospect of success. Israel can end Iran’s unlawful acts by ending its own unlawful act of aggression against Iran. Both Israel and Iran are violating international law at the same time, in somewhat different ways, and both must stop.
Now consider Lebanon. Israel’s use of force on Lebanon’s territory is not authorized by the Security Council. Is it a lawful exercise of Israel’s right of self-defense? No. The reason is the same. There is no necessity for Israel to use force in Lebanon because Israel could end Hezbollah’s unlawful acts by ending its own unlawful act of aggression against Iran. Hezbollah entered the war in response to Israel’s killing of Iran’s Supreme Leader, and reportedly plans to end its strikes as part of a regional ceasefire that includes Iran and the United States. Many of Hezbollah’s strikes appear to violate international humanitarian law and inexcusably harm civilians. But Israel does not need to use force in Lebanon to protect Israeli citizens. Israel can instead end its unlawful aggression against Iran. Again, both Israel and Hezbollah are violating international law at the same time, in somewhat different ways, and both must stop.
Israel may enjoy a limited right of “interstitial” self-defense to protect its citizens while it ends its own unlawful use of force and clearly communicates that it is doing so. There may be a brief period of uncertainty, mutual distrust, and poor discipline in which exchanges of fire may continue, and Israel may be obliged to protect its citizens with the minimal force necessary while attempting to deescalate and end the conflict. If Israel definitively ends its attacks on Iran, but Iran or Hezbollah persist in their strikes against Israel, then a new situation may arise in which Israel’s right of self-defense may be properly exercised for the first time. But this seems unlikely.
The illegality of Israel’s military campaign in Lebanon does not depend on a strict interpretation or application of the necessity requirement. Quite the contrary. The necessity requirement may or may not oblige a State to sacrifice its legal rights, or perform or refrain from a discretionary act, instead of using force in self-defense. Leave all such questions aside. It is self-evident upon reflection that the necessity requirement must oblige a State to end its ongoing violation of a peremptory norm of international law (jus cogens) such as the prohibition of aggression before it may lawfully resort to the use of force in self-defense. This is the absolute bare minimum that the necessity requirement must involve for it to place any meaningful constraints on a State’s use of force. If immediate cessation of a continuing act of aggression against one State is not a reasonable alternative to using force against another State then nothing is, and the necessity requirement requires nothing at all.
This necessity-based analysis does not depend on a dogmatic interpretation of the Nuremberg Tribunal’s statement that “he who initiates aggressive war loses the right to claim self-defense” drawn from the “long-established principle of criminal law” that “’there can be no self-defense against self-defense.’” The point is not that Israel, as the initial aggressor, forever forfeits its right of self-defense and can never regain it due to unclean hands. If Israel ends its aggression and clearly communicates that it is doing so, but Iran or Hezbollah persist in fighting, then Israel’s right of self-defense may very well resurface. But Israel must end its aggression first.
The preceding analysis also does not depend on any artificial separation of aggression and self-defense (jus ad bellum) from international humanitarian law (jus in bello). The point is not that Hezbollah or Iranian strikes directed at civilian populations violate international humanitarian law but do not, as such, constitute an unlawful armed attack that could trigger Israel’s right of self-defense. The point is that, even if such strikes constitute an unlawful armed attack, the use of defensive force in response is not permitted when it is unnecessary, and it is unnecessary when the reasonable alternative is simply ending an ongoing act of aggression.
The necessity requirement is often leniently applied once an armed attack begins. Most victims of an unlawful armed attack will reasonably conclude that no reasonable alternatives to the use of defensive force remain. Third States may continue to urge dialogue and deescalation while refraining from harsh criticism of the defending State, which may be slow to trust the prospects of a negotiated settlement. But the initial aggressor knows perfectly well that a reasonable alternative exists to continued fighting and the necessity requirement should be strictly applied to them.
The preceding analysis does not depend on Hezbollah’s legal status. Hezbollah is generally viewed as a non-State actor with both a political wing and a military wing. It is at best controversial whether acts of violence by a non-State actor constitute an “armed attack” that can trigger a State’s right of self-defense or permit the use of force on the territory of another State without its consent. But even if Hezbollah’s acts could trigger Israel’s right of self-defense, Israel may not exercise its right of self-defense unless it is necessary for Israel to use force in Lebanon to halt or repel armed attacks by Hezbollah. It is not. Israel can end any armed attacks by Hezbollah by ending its own unlawful armed attacks against Iran.
In short, Israel’s military campaign in Lebanon is illegal even on the assumption that Israel’s right of self-defense is engaged by Hezbollah’s strikes. Even on that assumption, Israel’s military campaign would still violate the necessity requirement internal to the right of self-defense and would be illegal on that basis.
Israel and the United States must end their ongoing war of aggression against Iran, and Israel must end its unnecessary military campaign in Lebanon. Iran and Hezbollah must end their illegal strikes directed at civilian populations. This multi-front war has cumulatively killed over a thousand civilians, including hundreds of children, destroyed countless homes, damaged several hospitals and cultural sites, and decimated civilian infrastructure. It must end now.
– Adil Ahmad Haque, Published courtesy of Just Security.
