This Article argues that international tax law has developed the characteristics of an asymmetric regime complex; contests over its normative content are playing out simultaneously in the OECD and in the UN. The OECD provides technical rulemaking capacity, while the UN serves to address claims about legitimacy and equity. Powerful states—especially China and the United States—have been exploiting the overlap between the two institutional arenas to try to press their competing visions for domestic and international tax governance.

The most-favored-nation obligation, as an expression of a non-discrimination norm, is often described as fundamental for international trade law. But does MFN deserve this normative halo? This Article traces the historical emergence of MFN-as-fundamental mythology, unearthing its origin in three controversial twentieth-century projects. Rather than promoting non-discrimination, MFN was historically used to draw discriminatory boundaries—between imperial powers and colonies and between West and East. Only with the ordoliberal turn did MFN become synonymous with a universalist, non-discrimination-centric international trade law. But history also reminds that alternative norms once vied to structure international trade law. Those may be due for reconsideration.