In an era when many fear the breakdown of the global trading order through the emergence of relatively closed regional trading blocs, assessing the effects of European integration on external European Union trade is particularly important. Surprisingly, despite a severe recession accompanied by record levels of unemployment, a history of increasing protection under similar economic circumstances, and alarming predictions about “fortress Europe,” external trade policy in the region has liberalized in recent years. Prominent trade policy explanations emphasizing changing interest group demands or changing ideas of policymakers are inadequate to account for this significant change in trade policy. Instead, much of this liberalization can be best understood as an unforeseen consequence of the Single European Act. Completing the single market undermined the effectiveness of national trade measures and made it difficult to enact new trade barriers, thus producing a liberal bias in European policy.