In this chapter, I discuss in what sense and to what extent institutions have political authority. I take institutions with legitimate authority to be justified in wielding political power, where this political power is backed by the threat of coercion. Against the position that international institutions are not coercive, I claim that applying an adequate conception of coercion – which takes the concept of enforcement as paradigmatic for coercion, rather than the concept of pressure – enables us to understand some international institutions as coercive. It also lays open the assumption that a single conception of authority applied to all international institutions misconceives the diversity in aims and purposes of international institutions. Institutions that coordinate morally mandatory aims and institutions that coordinate mutual advantage can both be plausibly understood as coercive, even though their authority differs in scope and in what standards they must satisfy. Finally, I discuss whether the standard of state consent is appropriate for international institutions: while it is plausible for institutions that coordinate mutual advantage, it is implausible as a standard of legitimacy for institutions that coordinate morally mandatory aims – such as institutions of international criminal justice.

The authors begin by observing that most obligations of international law are still regarded as ‘based’ on State consent. There are good reasons for this, especially from a democratic legitimacy perspective. Still, the principle of State consent, even in its qualified version of ‘democratic State’ consent, suffers from important shortcomings that call for correctives. The chapter starts by accounting for the democratic value of State consent in International Organizations (hereafter IOs) before addressing some of its democratic deficits. It then articulates several institutional proposals to correct or, at least, complement the role of equal State consent in the institution, the operation and the control of IOs. The authors develop a non-ideal normative argument for the latter’s political re-institution. That re-institution has to start with the replacement of the principle of equal State consent by that of equal public participation in IOs: this does not only avoid reducing State consent in IOs to State veto or refusal rights, but it also extends the personal scope of those participatory rights to other non-State public institutions.

The chapter examines the ICJ’s contribution to the law on the use of force. The author considers the Court’s case law on the prohibition of the use of force and its potential exceptions, most notably the law on individual and collective self-defence. He identifies the main conceptualisations, inconsistencies, disagreements, and limitations of the Court’s opinions, arguing that although the Court initially had a significant influence, it has faded significantly over the years as a result of what appears to be a conscious or strategic decision of its judges.

Sovereign States are under a legal obligation to comply with customary international law even though they have not explicitly consented to these norms. How should international courts accommodate both such non-consent-based CIL and a commitment to state sovereignty? The article outlines one strategy that avoids or helps address challenges wrought against other attempts to create more consistency and coherence between CIL and the other sources of international law – whilst securing a central role for state consent. A plausible account of why states have an obligation to honour treaties they consent to also contributes to justify their obligation to honour CIL norms. The shared normative basis for both sorts of obligations may be a ‘Principle of Non-manipulation’, a norm to not violate intentionally created rightful expectations. The account draws much on Scanlon, MacCormick and Hart.