The conditioning effect of EU membership status: understanding compliance with legislative initiatives to protect trafficking victims

European countries face a tremendous challenge in coping with human trafficking, a challenge that has been exacerbated by the increase in irregular forms of migration to Europe since 2015. European Union members have made progress in developing a legal framework to protect trafficking victims. Yet attempts to coordinate national laws fail to address the growing problem. Research is needed to understand why states fall short of EU goals. Through case studies of Germany, Hungary and Turkey, we examine the extent to which adoption of the European Union’s Council Framework Decision on Combating Trafficking in Human Beings is associated with positive domestic changes. We focus on the effect of European Union membership status on implementation of victim protection policy. The results suggest that powerful EU members need incentives to cooperate that exceed costs, while capacity-building measures would likely drive change for candidates and newer members. Our findings help scholars predict when European legislative initiatives will likely translate into better domestic anti-trafficking measures. The findings also have broader implications for cooperative efforts in migration control and human rights protection.