Since the mid-19th century, the US has been a Pacific power. Through three wars and the Cold War, America became a major regional player. Modern Japanese-American relations were shaped by the Cold War, and a strong political-military alliance served the geopolitical needs of both countries. As Japan’s economy matured and its politics transformed in the 1990s, Tokyo sought greater political independence, and used an upgrading of the alliance as part of its effort to achieve the more “normal” status as a great power. US relations with South Korea have been driven by a shared perception of threat from North Korea. Since the Cold War, the nature of this threat has shifted from immediate concern about conflict to danger from an essentially failed state. Sino- American relations centre on the interaction of two great powers. China’s quasi-alliance with the US and market-oriented reforms meant that the relationship in the 1980s centred on reintegration of China into the global political economy. Since the mid-1990s, China’s “rise” has led to increased tensions, especially in strategic and economic issue areas. America’s close but unofficial relationship with Taiwan remains an irritant to overall Chinese- American ties.