This article investigates how commercial ties affect the cohesiveness of US alliances with East Asian nations. While the conventional wisdom views their effects as positive, we argue that economic interdependence does not markedly reinforce East Asian alliances because the alliances have an asymmetrical structure. To evaluate these competing arguments, we examine the impact of bilateral trade on the US alliances with Japan, Taiwan, the Philippines, and South Korea, over the past quarter-century. Our empirical analysis provides little evidence for the conventional view, while supporting our argument. Based on this finding, the article offers some practical implications for the free trade agreement and the security alliance between South Korea and the USA.