The recent defence and nuclear cooperation pact between Saudi Arabia and Pakistan has ignited considerable global attention. Its most surprising clause declares that “any aggression against either country shall be considered an aggression against both.” While this language resembles NATO’s Article 5, its implications in the nuclear and Middle Eastern context are far more precarious. The pact raises difficult questions about the prohibition on the use of force, collective self-defence, and state responsibility when deterrence arrangements violate the realms of sovereignty and accountability.
At the heart of this debate lies Article 2(4) of the UN Charter, which forbids the threat or use of force against the territorial integrity or political independence of any State. This principle is often regarded as the cornerstone of international law, which was aimed at preserving global peace and preventing unilateral aggression. The UN Charter allows only two exceptions: self-defense under Article 51 and collective enforcement actions authorized by the UN Security Council. Yet, in practice, defence alliances and proxy interventions have repeatedly challenged this framework, often testing the limits of its legality.
The Saudi–Pakistan pact meets at this intersection; if an external power attacks Saudi Arabia and Pakistan respond militarily or vice versa, such action could be justified as collective self-defence under Article 51. However, if either party unilaterally interprets a perceived threat as “aggression” and launches pre-emptive or disproportionate force, the legality of that response would be a matter of debate.
To evaluate such commitments, there exists the Articles on Responsibility of States for Internationally Wrongful Acts (ARSIWA), which was adopted by the International Law Commission. ARSIWA establishes the rules for attributing conduct to States and determining international responsibility. For example, Articles 4–11 outline how acts of organs or entities are attributed to a State.
Two major tests emerge from international jurisprudence. The effective control test, articulated by the ICJ in Nicaragua v. United States (1986), attributes responsibility only when a State exercises control over specific operations leading to a wrongful act. The overall control test, developed by the ICTY in the Tadić case (1999), is broader, it attaches responsibility where a State has general oversight, coordination, or financial support over an operation.
Applied to the Saudi–Pakistan pact, several legal concerns arise. If Pakistan extends its nuclear umbrella or provides military assets to Riyadh in response to perceived aggression, will that qualify as lawful collective defence? Conversely, if such assistance is preemptive, retaliatory, or disproportionate, could Pakistan be held internationally responsible under ARSIWA Articles The same question applies if Saudi Arabia intervenes in Pakistan’s regional disputes, such as along its western border.
The clause that “any aggression against either shall be considered aggression against both” symbolizes solidarity but risks mutual liability. Under Article 51, collective self-defense is lawful only when an armed attack actually occurs and when the response is necessary and proportionate. If one State’s subjective interpretation of “aggression” triggers retaliation by both, the arrangement could lead to unlawful escalation.
Ultimately, the Saudi–Pakistan pact represents both a strategic innovation and a legal risk. It reflects a regional aspiration for shared security in a multipolar order but simultaneously challenges the established provisions of lawful force and state accountability. To align the agreement with international law, both States should clearly define the term “aggression”; establish joint verification mechanisms before invoking collective defence; and affirm that any use of nuclear or conventional force will remain strictly defensive and proportionate.
Going forward, the lessons learnt from ARSIWA and ICJ jurisprudence is that shared defence cannot justify shared violations. Genuine responsibility in international law requires restraint, transparency, and adherence to the UN Charter’s core principles.
[Photo by Saudi Press Agency/Reuters]
