The United States entered the 21st century actively pursuing a “go-it-alone” approach to international relations. This is especially the case in global environmental affairs, where the United States is now widely perceived as a laggard and even an obstacle to collective action. Yet, the United States was the prime proponent and creator of international environmental organizations in the 1970s. In this article, we analyze the U.S. role in global environmental governance from a historical perspective and present a platform for U.S. re-engagement. We contend that the new U.S. Administration should re-examine its strategy towards global environmental concerns and reinstate a commitment to multilateralism as well as to playing a leadership role.