Institutional Design and Normative Authority in the Effectiveness of the IAEA Nuclear Security Mandate

Abstract The International Atomic Energy Agency exercises significant nuclear security governance authority without possessing the enforcement powers mandatory inspection, binding accountability findings, sanction authority that conventional accounts of international institutional effectiveness treat as necessary conditions for compliance generation. This paper investigates the theoretical sources of the IAEA's governance authority, arguing that a single-theory account whether liberal institutionalist or constructivist is insufficient to explain either the IAEA's achieved governance successes or its persistent governance failures in the nuclear security domain. Drawing on a systematic analysis of 112 governance documents (2004–2025) and five semi-structured expert interviews, the paper applies an integrated liberal institutionalist-constructivist analytical framework to the IAEA nuclear security case, demonstrating that the two traditions are complementary rather than competing explanations of institutional effectiveness in this domain. Liberal institutionalism explains the IAEA's compliance-generating capacity through its institutional design features the Nuclear Security Series as credible technical standards, the IPPAS programme as monitored compliance assessment, and the INSSP as structured assistance delivery while constructivism explains the normative socialisation mechanism through which states internalise nuclear security standards even in the absence of binding enforcement authority. The integrated analysis generates three original findings. First, the IAEA's governance effectiveness is best explained by what Barnett and Finnemore (2004) term its "expert authority" the combination of technical expertise and normative legitimacy that enables an advisory institution to shape state behaviour without coercive capacity. Second, the compliance facade problem identified in companion analysis is theoretically rooted in the divergence between the rational-institutional compliance logic that liberal institutionalism predicts (states comply because they calculate that compliance generates benefits) and the constructivist normative logic that the IAEA's governance design assumes (states internalise nuclear security standards through socialisation into a nuclear security culture). Third, the Barnett-Finnemore organisational authority framework requires extension to accommodate the specific pathology of advisory institutions in security-critical domains: the expert authority that enables compliance under favourable political conditions is insufficient to generate compliance when states' strategic interests actively conflict with governance obligations. The paper develops two theoretical propositions that extend the Barnett-Finnemore framework to the nuclear security advisory mandate case and draws implications for the design of international institutions in security-critical advisory domains.