Israel, Qatar, and the Limits of Self-Defense

On Sept. 9, Israeli forces carried out airstrikes in Doha, targeting a Hamas office and killing five Hamas members along with a Qatari security officer. The strike landed only a few hundred meters from a Qatari-U.S. mediation meeting advancing a ceasefire proposal. This was no marginal incident. It marked the first time Israel openly struck in Qatar, a neutral Gulf state that also hosts the largest U.S. military base in the region.

The international reaction was swift. The UN Security Council condemned the strike unanimously—including the United States, breaking its pattern of vetoes. Arab and Islamic states convened an emergency summit, pledging coordinated measures. Qatar’s Prime Minister Sheikh Mohammed bin Abdulrahman bin Jassim Al-Thani captured the outrage: “We were thinking that we are dealing with civilized people …. And the action that (Netanyahu) took – I cannot describe it, but it’s a barbaric action.”

Following strong diplomatic pressure, Israeli Prime Minister Benjamin Netanyahu issued an unprecedented apology to Qatar, conveyed in a phone call facilitated by President Trump. Netanyahu assured Doha that “Israel has no plan to violate [Qatari] sovereignty again in the future.” While this apology marked a rare moment in Israeli diplomacy, it also underscored the magnitude of the violation.

Just weeks later, on Sept. 29 President Trump signed an executive order entitled “Assuring the Security of the State of Qatar.” The order recognizes the “enduring alliance” between the United States and Qatar and provides an explicit U.S. security guarantee: Any armed attack on Qatari territory will be regarded as a threat to the peace and security of the United States, triggering “all lawful and appropriate measures—including diplomatic, economic, and, if necessary, military—to defend the interests of the United States and the State of Qatar.” This guarantee, unprecedented for any Arab state, was widely understood as a direct response to Israel’s strike and an attempt to restore Qatar’s trust in Washington’s mediation framework.

The Doha strike was a serious violation of international law. It breached the UN Charter’s prohibition on the use of force, failed to meet the conditions of necessity and proportionality under Article 51, disregarded the rights of a neutral state under the Hague Conventions, and undermined the principle of peaceful dispute settlement in Article 33. Legally, Israel cannot stretch self-defense to cover extraterritorial assassinations on the soil of a neutral state. Politically, the attack risks normalizing preventive war.

Legal Violations

Article 2(4) of the charter prohibits “the threat or use of force against the territorial integrity or political independence of any state.” Qatar is not a belligerent in the Gaza war. Absent Security Council authorization, Israel’s only potential legal basis is Article 51, which preserves “the inherent right of individual or collective self-defense if an armed attack occurs.”

But as the International Court of Justice (ICJ) has repeatedly affirmed—in Nicaragua v. United States (1986), Oil Platforms (2003), and Armed Activities on the Territory of the Congo (2005)—Article 51 permits only necessary and proportionate measures in response to an actual armed attack, and cannot justify preventive or open-ended military campaigns. The ICJ has underscored two cumulative conditions: necessity (force must be the only way to halt an imminent or ongoing attack) and proportionality (the defensive action must not exceed what is strictly required to repel that attack).

In addition, Article 33 of the charter obliges parties to disputes “the continuance of which is likely to endanger the maintenance of international peace and security” to seek resolution by peaceful means, including mediation. Qatar was engaged in precisely such efforts when it was struck.

Israel has argued that the targeted Hamas leaders were directly responsible for atrocities, including the Oct. 7, 2023, massacre, and that Hamas itself claimed responsibility for bombings inside Israel. These facts underscore Hamas’s culpability. But, as explained below, international law requires more than past responsibility.

Israel has suggested that its strike falls within a broader understanding of self-defense against a continuing armed campaign by Hamas. On this view, every Hamas leader, regardless of location, constitutes a legitimate target because the group remains actively engaged in hostilities against Israel. This argument echoes the U.S. position after the Sept. 11 terrorist attacks, when Washington claimed that the “armed attack” by al-Qaeda was ongoing and that force against its leaders abroad was therefore lawful. Yet the ICJ has consistently resisted such elastic interpretations, insisting that legality must be judged by the circumstances at the moment of the strike. Treating past atrocities as an open-ended license for future uses of force collapses the requirement of imminence and converts Article 51 into a general charter for preventive war—a move the court has refused to accept.

As the ICJ explained in Oil Platforms, the legality of a use of force must be judged by reference to the circumstances as they existed at the time the action was taken, applying the strict and objective criteria of necessity and proportionality—not in light of subsequent events or prior attacks alone. By Sept. 9, there was no evidence that Hamas leaders in Doha were directing imminent armed operations from Qatari soil.

The customary law standard, articulated in the 1837 Caroline incident, remains binding: The necessity of self-defense must be “instant, overwhelming, leaving no choice of means, and no moment for deliberation.” That threshold was not remotely satisfied. Israel had time to consult the Security Council, coordinate with Washington, or request Qatari cooperation. Its unilateral resort to force collapsed the necessity requirement.

The Sept. 9 strike also violated the law of neutrality. The 1907 Hague Convention V, Article 1, provides that “the territory of neutral Powers is inviolable.” Article 2 prohibits belligerents from moving troops or conducting hostilities in neutral territory. Neutral states may not allow their territory to be used as a base of operations, but mediation and diplomacy do not transform them into belligerents.

Nor did Israel show that Qatar was unwilling or unable to act to prevent Hamas’s armed operations. Israel and the United States have relied on the controversial “unwilling or unable” doctrine to justify strikes in Syria and Iraq. But Doha is not Damascus. Since 2012, Hamas’s political bureau has been openly hosted in Qatar with the tacit consent of both Washington and Jerusalem, precisely to enable mediation. At the time of the strike, Qatari officials were facilitating hostage-release and ceasefire negotiations. Far from being unwilling, Doha was actively engaged in diplomacy.

Even under the “unwilling or unable” framework—which many states reject as lacking customary law status—Israel failed to demonstrate that Qatar permitted Hamas to mount attacks from its territory. Using the doctrine here would invert its rationale and weaponize it against mediation itself.

Some defenders argue that once an international armed conflict (IAC) exists between Israel and Hamas, the legality of subsequent strikes should be assessed under jus in bello—the law of armed conflict—not jus ad bellum. Jus in bello regulates conduct in war; jus ad bellum governs the resort to war. They operate in parallel. As the ICJ has observed, compliance with international humanitarian law does not excuse violations of the charter’s prohibition on force.

Under this view, the only relevant question is whether the targets were “military objectives” under Article 52 of Additional Protocol I.

This argument fails for two reasons. First, Qatar is not a party to the IAC between Israel and Hamas. Attacking targets on Qatari soil therefore cannot be subsumed under the jus in bello framework without collapsing the line between neutral and belligerent states. Second, even if jus in bello applied, jus ad bellum continues to operate in parallel: States must still justify the resort to force against the sovereignty of another state. Israel cannot immunize itself from charter review by relabeling the strike as a continuation of hostilities.

Stretching Article 51 Beyond Its Limits

The weakness of Israel’s self-defense claim becomes even clearer when compared to other attempts by states to stretch Article 51 beyond its accepted limits.

One prominent example is the United States’s use of drone strikes in Pakistan, Yemen, and Somalia. Washington repeatedly invoked the “unwilling or unable” doctrine to justify operations against al-Qaeda and Daesh affiliates located in these states. Yet many of the affected states—including Pakistan and Yemen themselves—rejected this rationale and condemned the strikes as violations of their sovereignty. Far from settling into customary international law, the doctrine remains highly contested, with most states refusing to endorse it.

Turkey has likewise relied on self-defense to justify its repeated incursions into northern Iraq and operations in Syria against the PKK—which it, along with the United States and European Union, designates as a terrorist organization—and against the YPG, a Kurdish militia that Ankara views as affiliated with the PKK but whose status is disputed internationally. Ankara has argued that Baghdad and Damascus were “unable” to prevent cross-border attacks, and it has formally cited Article 51 in its communications to the UN Security Council. But most states have refrained from endorsing Turkey’s reasoning, viewing such cross-border operations as exceptional claims that strain the accepted limits of self-defense.

Russia’s 2022 invasion of Ukraine illustrates the dangers of accepting such expansive claims. Moscow attempted to frame its aggression as anticipatory self-defense, invoking alleged NATO encroachment and supposed “genocide” in Donbas. The global reaction—near-universal condemnation and widespread isolation of Russia—underscored that preventive self-defense claims remain incompatible with the UN Charter framework.

Taken together, these cases demonstrate that the broader doctrines advanced by Israel and the United States are exceptional rather than reflective of settled law. State practice overwhelmingly supports the International Court of Justice’s narrow approach, under which necessity must be immediate, overwhelming, and strictly proportionate to an imminent or ongoing attack.

The legal irony is that Israel itself long tolerated—and in Hamas’s early years, indirectly enabled—the group’s rise as a counterweight to the Palestine Liberation Organization. In later decades, Israel accepted Qatar’s hosting of Hamas’s political bureau, using Doha as a channel for ceasefire talks and negotiations. That history undercuts Israel’s self-defense claim: Hamas’s presence in Qatar was not clandestine, but long acknowledged in the context of regional diplomacy. Israel cannot now recast it as an unlawful sanctuary to justify violating Qatari sovereignty

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Israel’s Sept. 9 strike on Doha was unlawful under international law. It breached Article 2(4) of the UN Charter, failed the necessity and proportionality requirements of Article 51, and undermined both neutrality and peaceful settlement norms.

Even if Hamas leaders in Doha bore responsibility for past atrocities, that does not license preventive war. The law requires imminence, necessity, and host-state unwillingness. None were present. To normalize such actions would be to erode the charter system itself—reducing Article 2(4) to a dead letter and encouraging states worldwide to cloak preventive wars in the rhetoric of self-defense.

Going forward, the Security Council and regional organizations should reaffirm the inviolability of neutral states engaged in mediation. The law of neutrality, once central to international order, has been neglected in recent decades; reviving it is essential if diplomacy is to function in today’s conflicts. The United States in particular faces a choice: tolerate strikes that undermine its own mediation partners, or take a clearer stand that self-defense claims cannot be weaponized against neutral states facilitating negotiations. Establishing that boundary now could help prevent future erosion of the charter system and protect the fragile space for diplomacy in other conflicts.

As Sheikh Mohammed noted, the strike was not only unlawful but “barbaric.” It shatters trust at the very moment diplomacy was underway. Qatar’s prime minister captured the deeper danger: “Attacking our territories while we were busy with negotiations has uncovered the intention of Israel.” Such actions do more than undermine a single round of talks—they erode the very possibility of negotiated peace. If the international community fails to respond, the line between war and peace risks disappearing altogether.