Gulf foreign ministers last month did something they rarely do. In their Oct. 18 postsummit communique, they invoked the joint defense agreement signed in Manama in December 2000: an attack on one member, they said, is an attack on all six. Days later, Houthi attacks put the area around Makkah in danger. On Sunday, the Coalition to Restore Legitimacy in Yemen struck Houthi missile and drone sites. The next day, another ballistic missile was intercepted over southern Saudi Arabia.

The words, then, have been said. The harder question is legal. What does the Gulf’s defense pact actually require and has anyone yet done it?

The agreement is unambiguous. The member states regard aggression against any one of them as aggression against all and commit to assisting the state attacked with all necessary measures, including military force. That is not a declaration of friendship. It is a treaty obligation.

Nor does it stand alone. Article 51 of the UN Charter preserves the right of collective, not only individual, self-defense. Article 52 expressly recognizes regional arrangements such as the Gulf Cooperation Council as legitimate instruments of peace and security. Beneath both sits the Arab League’s Joint Defense Treaty of 1950. The Gulf does not need a new law to stand together. It needs to use the law it already has.

Any response must respect necessity and proportionality. Collective defense is a shield, not a sword

Dr. Bashayer Al-Majed

Collective self-defense has conditions and the International Court of Justice set them out in the Nicaragua case of 1986. There must be an armed attack. The state attacked must declare that it has been attacked and ask for help. Collective defense cannot be imposed on a victim; it must be invited.

The first condition is plainly met. Repeated missile and drone strikes on civilian airports and energy infrastructure are an armed attack by any reasonable definition. The second is a matter for Riyadh, which has so far relied on its own forces while keeping diplomacy open. That restraint is wise and it strengthens the Kingdom’s legal position.

There is a third step that is often forgotten. Article 51 requires that measures taken in self-defense be reported immediately to the UN Security Council. A formal Saudi notification, joined by letters from its Gulf partners, would turn a communique into a legal record. It would also place the burden where it belongs: on the attackers and on those who arm them in breach of UNSC Resolution 2216.

Any response must respect necessity and proportionality. Collective defense is a shield, not a sword. It permits what is needed to stop the attacks, not to settle older scores. That limit is what gives it legitimacy.

On paper, the Gulf has the architecture of a real alliance: the Peninsula Shield Force, a Unified Military Command headquartered in Riyadh and joint air defense and maritime security initiatives. In practice, solidarity has been less reliable. The rift with Qatar between 2017 and 2021 showed how quickly politics can freeze the machinery of cooperation. The AlUla Declaration restored relations but left an open question: Is Gulf solidarity a binding obligation or something that holds only when politics allow?

This crisis is the first serious answer. Its outcome will shape the region’s security for a generation.

Is Gulf solidarity a binding obligation or something that holds only when politics allow? This crisis is the first serious answer

Dr. Bashayer Al-Majed

It would be a mistake to treat this as Saudi Arabia’s crisis alone. Attacks on its airports threaten the airlines and passengers of every Gulf state. Threats to shipping in the Strait of Hormuz and the Bab Al-Mandab Strait touch every Gulf budget. Gulf economies rise and fall together.

Kuwait understands this better than most. In 1990, Saudi Arabia opened its territory, airspace and ports to restore a neighbor’s sovereignty. Kuwaitis remember. Our history is the clearest evidence in the region that small states survive through alliances and that alliances survive only when they are honored. That obligation runs in both directions.

Solidarity need not mean deploying troops. It can mean integrated air defense, shared intelligence, joint notifications to the UNSC, a common position at the UN and a single voice demanding that those who direct these attacks be held to account.

What it cannot be is a statement and nothing more. A defense pact invoked only in communiques is not a shield. It is a ceremony. On Oct. 18, the Gulf said the words. The law now asks it to act on them.

  • Dr. Bashayer Al-Majed is a professor of law at Kuwait University, and a visiting fellow at Oxford.

X: @BashayerAlMajed