Resources for the Future and the Institute for Global Environmental Strategies (Japan) convened a one-and-one-half day workshop on domestic and international climate policy on February 12-13, 2004 in Washington, D.C. On the first day, 55 participants heard presentations from 14 speakers and discussed domestic activities, economics, and politics. The second day featured a smaller group of 27 participants hearing six informal sets of comments and discussing opportunities for international collaboration. Participants included government officials from the Japanese Ministry of the Environment, the U.S. Environmental Protection Agency, and other U.S. administration and congressional staff; representatives from business and environmental groups; and academic experts. Over the course of both days, it was clear that great opportunities exist for informing participants from both countries on recent developments, economic analyses, and political nuances in the other country. For example, American participants were unaware of the Keidanren's success at exceeding required efficiency standards. Japanese participants were unaware of U.S. treaty tradition, by which ratification cannot occur until implementing legislation is in place-a fact that makes the Kyoto Protocol virtually unratifiable. Participants on both sides benefited from a frank discussion of how and why it may be unwise for the international community to attempt to re-engage the United States in international climate policy until the United States settles on its own course of meaningful domestic action. Looking forward, an important lesson may be taken from U.S. experience with early environmental regulation, where state action provided experience and impetus for federal action. As an alternative to the Kyoto model, distinct national actions may provide experience and impetus for international action. In addition, policies in both the United States and Japan reflect a strong emphasis on technology development and commercialization; this may be an area where bilateral cooperation could be particularly beneficial.