Even after the departure of two of its most prominent advocates - Chief Justice William Rehnquist and Justice Sandra Day O\u27Connor - the federalism revolution initiated by the Supreme Court almost twenty years ago continues its onward advance. If recent court decisions and congressional legislation are any indication, in fact, it may have reached a new beachhead in the realm of foreign affairs and international law. The emerging federalism in foreign affairs and international law is of a distinct form, however, with distinct implications for the relationship of sub-national, national, and international institutions and interests. This article draws on the prism of coordination, as well as related analysis of standard-setting, to questi...