Assessing the legality of ‘use of force’ against heads of states under international law

Abstract

This dissertation examines the legality of the ‘use of force’ against Heads of State under International Law, focusing on how contemporary state practice has tested and, at times, strained the Charter-based framework governing the use of force. The study further finds that immunity provides only limited protection. While personal immunity shields incumbent Heads of State from foreign jurisdiction, it regulates accountability rather than the legality of military force. This creates a structural gap: Heads of State enjoy extensive protection from judicial processes but not equivalent protection from coercive force. Although sovereignty, political independence, and non-intervention indirectly constrain leadership-targeted operations, such force may still be justified under recognised exceptions, including self-defence and Security Council authorisation, leaving its legality uncertain. The study also identifies an unresolved tension between sovereignty and accountability. Although International Criminal Law increasingly promotes accountability for state leaders, it does not clarify whether force may be used to achieve that objective. Instead, states continue to justify leadership-targeted operations through existing doctrines such as self-defence, counter-terrorism, and humanitarian protection. While these practices challenge traditional assumptions, they have not established a new legal norm permitting such force, and international responses remain inconsistent and politically influenced. The study therefore concludes that the protection of Heads of State remains indirect, fragmented, and contested. Although sovereignty, political independence, and immunity impose important legal constraints, they do not create a comprehensive prohibition on leadership-targeted force. Nevertheless, the continued reliance on Charter-based justifications confirms the enduring normative authority of the prohibition on the use of force and the principle of sovereignty. Violations of the prohibition of the use of force principally engage the responsibility of the injured State, while the Head of State, as the immediate target and victim of the operation, enjoys no corresponding individual remedy under the regime. This disconnect exposes an important normative gap between the individual harm suffered and the collective, inter-State mechanisms through which International Law responds to unlawful uses of force. The study contends that leadership-targeted force exposes under-theorised tensions within the existing legal framework, raising distinct questions concerning sovereignty, attribution, immunity, accountability and the limits of lawful self-defence. It concludes that although the Charter regime remains formally intact, its interpretation is undergoing a gradual and contested evolution driven by emerging state practice and shifting security paradigms.