Chapter 4 examines the uneven history of supranationalism in the postwar international trade regime, focusing on the practice of dispute settlement. I first note the significant shift in constitutional principles between the GATT and the WTO, arguing that the key move concerned not the shift from diplomacy to law as many scholars emphasize but the shift from intergovernmentalism to supranationalism in dispute settlement practices. The willingness of governments to accept the WTO’s supranational authority was made possible, I argue, by a transformation in how governments understood the purpose of the international trade regime. Beginning in the 1980s, international trade increasingly came to be seen as an activity that implicates the interests of not only governments but also transnational actors, such as corporations, traders, and individuals. A more legalized dispute settlement process was seen as necessary in order to provide the stability and predictability needed for private actors to pursue international trade. This chapter also examines the ratification debates in both the US and Europe over the proposed WTO, showing how concerns over sovereignty structured these debates. I trace how advocates for the WTO in the US were able to rhetorically outmaneuver those voices who expressed concerns about the loss of sovereignty and how the ratification debates within Europe led to a reconsideration of the supranational authority of the European Commission with significant implications for the common commercial policy of the EU.