This proposed project has two aims: (1) to describe collective identity formation in the U.S. -Japan alliance after the end of the Cold War from the perspective of American elites (the dependent variable); and (2) to explain the facilitating and hampering factors for the variance (independent variables). I also plan briefly to compare this alliance with the U.S. -U.K. and U.S.- Saudi Arabia alliances in order to make a relative assessment of collective identity formation and to gain more confidence in my estimation of possible causal factors such as interdependence, common fate, and homogeneity. The findings of this research are expected not only to contribute to the theoretical and methodological development of social constructivism but also to have several practical implications for contemporary policy debates on U.S. -Japan relations.