As an ITER partner, the United States will have an opportunity to explore, with ITER’S other partners, the frontiers of plasma science and to bring the promise of fusion energy closer to realization. Seven international partners, China, the European Union, India, Japan, the Republic of Korea, Russia, and the United States, representing more than half of the world population, will have access to the scientific results. The success of ITER will depend on each partner’s engagement in addressing the scientific and technological challenges of advancing our understanding of fusion. In this report, a National Research Council committee assesses the current U.S. Department of Energy’s plan for U.S. participation in ITER and recommends goals, procedures, and metrics to be included in future versions.