This book examines a distinctive multilateral initiative developed in response to U.S. secondary sanctions amid the unresolved Iranian nuclear dispute. Although short-lived, INSTEX (Instrument in Support of Trade Exchanges) emerged as a regime-based attempt to navigate an increasingly politicized global financial order and to challenge the dominance of unilateral sanctions.
Drawing on regime theory, sanctions politics, and international political economy, the study analyzes the design, implementation, and failure of INSTEX as a case of institutional resistance. It explores to what extent INSTEX reflects the components of an international regime principles, rules, norms, and decision-making procedures and whether it can be considered a regime in its own right.

Furthermore, the book proposes a generalizable analytical model for operationalizing regime theory in international relations, offering a framework applicable to INSTEX-like mechanisms and similar institutional phenomena in the global order.

By situating INSTEX within the dynamics of the U.S.Iran confrontation and the broader sanctions regime, this work provides fresh insights into nuclear diplomacy, multilateralism, and institutional innovation in international relations.