The principle of non-intervention is widely acknowledged as a fundamental rule of customary international law. Yet the principle’s contours remain ill-defined. Particularly, it is unclear when unilateral economic measures may constitute ‘coercion’ and thus violate the principle. This thesis seeks to address this problem. Through a detailed examination of the conception of the notion of economic coercion in practice, it demonstrates that, while unilateral economic coercion is universally recognised as prohibited under the non-intervention principle, the precise scope of this concept is unclear under lex lata. While non-WEOG states have advocated an expansive definition of economic coercion encompassing almost all types of economic measures, WEOG states have been reluctant to characterise economic measures as coercive, favouring a flexible definition of economic coercion to maintain their freedom to influence the policy choices of other states. Given the uncertainty reflected in practice, the thesis proceeds to establish an analytical framework to provide further guidance on the identification of economic coercion. It identifies five groups of different approaches proposed by international lawyers for determining non-forcible coercion and highlights the weaknesses of each approach. It also resorts to domestic legal regulation of coercive economic pressure to shed light on the concept of economic coercion in international law. By doing so, it observes similarities in the historical development of both regimes and identifies certain common regulatory trends. Drawing on both domestic and international legal doctrines, the thesis proposes a three-step method to identify economic coercion under the non-intervention principle. Essentially, an economic measure constitutes coercion either because (1) it falls within a specific type of measures universally recognised as coercive or (2) it breaches international obligations of the sender state towards the target state and (3) has such significant effects that the latter has no reasonable alternatives to resist
