Just as the United States has gone back-and-forth on the strategic importance of Japan, Tokyo has debated the nature of its role in the international system. The resulting oscillation by both states necessitates a careful examination of Japan's importance. The U.S.-Japan security alliance enables strategic stability in Asia, and Japan remains both a potent economic force and a democratic anchor in the region. Both the United States and its European allies must consequently step up strategic dialogue and cooperation with Japan.