Constitutional law in the United States and around the world now operates within an increasingly transnational legal environment of international treaties, customary international law, multilateral and bilateral agreements, a supranational infrastructure of trade law and human rights law, and increased comparative judicial awareness, reflected in increasing cross-national references in constitutional court decisions around the world. The constellation of legal orders in which established constitutional regimes operate has thus changed - there are more bodies generating law, there are more international agreements, there are more multi-national interactions and transactions that bring into view various legal orders. How, if at all, do these multiple transnational phenomena (including national law that has influence beyond its borders, as well as an expanded array of international law) affect our understanding of the role of constitutions and of courts in deciding constitutional cases? Constitutional Engagement in a Transnational Era explores the role of constitutions and constitutional law, focusing primarily on the United States, Australia, Canada, France, Germany, India, Israel, South Africa and the United Kingdom, within and in relationship to this increasingly transnational legal environment.