This book addresses the role of domestic courts in the enforcement of international trade agreements by examining the experiences of Brazilian and the European Union courts. This comparative study analyzes the differences, similarities and consequences of Brazilian and European courts’ decisions in relation to the WTO agreements, which have “direct effect” in Latin American emerging economies, but not in the European Union or other developed countries. It observes that domestic courts’ enforcement of international trade agreements has had several unintended and counterproductive consequences, which were foreseeable in light of international scholarly debate on the direct effect of WTO agreements. It draws lessons from these jurisdictions’ experiences and argues that the traditional academic literature that fosters domestic courts’ enforcement of international law should be reconsidered in Latin America in relation to international trade agreements. This book defends the view that, as a result of their function and objectives together with the principles of popular sovereignty and democratic self-government, international trade agreements should not be considered to be self-executing or to have direct effect. This empirical work will be valuable to anyone interested in the effects of international trade rules at the domestic level and the role of domestic judges in international law.