Subsidiarity is the principle which the European Community has begun applying to consider whether federal legislation is necessary, or whether action by the Member States will suffice. This article considers whether subsidiarity should constrain the Court of Justice\u27s jurisprudence as well. It begins by analyzing the federalism problems posed by the Court\u27s case law concerning remedies for the violation of Community law, in particular the doctrine holding Member States liable in damages for failing properly to implement Community directives. After concluding that the Court is required to review this jurisprudence for consistency with the subsidiarity principle, and that the Court\u27s existing compensation and rights-centered rational...