Can an international organization socialize those who work within it? The European Commission of the European Union is a crucial case because it is an autonomous international organization with a vocation to defend supranational norms. If this body cannot socialize its members, which international organization can? I develop theoretical expectations about how time, organizational structure, alternative processes of preference formation, and national socialization affect international socialization. To test these expectations for the European Commission, I use two surveys of top permanent Commission officials, conducted in 1996 and 2002. The analysis shows that support for supranational norms is relatively high, but that this is more because of national socialization than socialization in the Commission. National norms, originating in prior experiences in national ministries, loyalty to national political parties, or experience with one's country's organization of authority, decisively shape top officials' views on supranational norms. There are, then, several roads to international norms.
