America’s relentless pursuit of primacy has been reinforced by the US-led military alliances in East Asia and the Pacific, better known as the ‘Hub and Spokes’ architecture (with the US as a ‘hub,’ and Australia, Japan, South Korea, the Philippines, and Thailand as ‘spokes’), which survived the end of the Cold War and continue to give unequivocal support for the US global business of maintaining its unchallenged supremacy over an international system, rather than form its own alliance against the only remaining superpower. Subtle differences may well have existed in the rationales for alliance management formulated and implemented from the early years of the postwar era to the present-day. As compared to the previous official US strategy and policy documents that have placed greater emphasis on reassuring the allies of Washington’s ‘strong’ commitment to their defense and security, the recent US strategy documents are certainly more focused on empowering them to play a greater or more active role in helping to maintain peace and stability across the region and the world, as well as cater for their own needs. It is then essential to gain a better understanding of the contributions some of the most capable allies of the US, especially Japan has made in this regard. Japan, once derided as apassive free-rider, now responds to security challenges at both regional and global levels, including China’s increasing aggression in the East and South China Seas, by building up practical defense cooperation in a wide range of fields with other US allies and partners while further deepening its already close alliance relationship with Washington. Japan continues to reinterpret the country’s pacifist Constitution that would allow the nation to expand the role of the Japan Self-Defense Forces (SDF) and its military capabilities.