A gap within the existing literature on regionalism is that it has yet to bring together intra- and inter- regional bargaining. By this, we mean that regional initiatives operate in the shadow of extra-regional great powers. Utilizing a simple game theoretical model, this project brings together intra- and inter- regional bargaining. Our discussion shows that the interaction between regional great powers, small-to-medium states within a region, and extra-regional great powers has played a critical though under-appreciated role in shaping the outcomes of different regionalism projects. With such a framework in hand, we then go on to discuss the interaction between U.S., China, and East Asian states within East Asian regionalism and explore possible conditions for U.S. and China to reach some kind of strategic accommodation between them.