There is no mistaking Prime Minister Abe Shinzo’s determination to transform Japan’s foreign and security policies and reassert itself in the world. In the four months since he took office, he has made considerable progress in that endeavor. Yet the prime minister conducts a delicate balancing act that becomes more difficult as he moves forward: While he must seize opportunities as he forges this new role, he must also reassure doubters both at home and abroad that Japan will act responsibly, and that its new power and influence will be put to good use. That requires a vision of Japanese power and a national strategy to use it. While the primary burden is Tokyo’s, the U.S., as its ally and partner, can play an important role in this effort.