The claim that transitions in international order are not only products of transitions in power, but also products of transitions in shared ideas is now relatively uncontroversial in the International Relations literature. Yet persistent gaps remain in understanding how ideas are shared, and which states play a role in sharing an international orderâ€™s ideas. This paper demonstrates that ideas are shared through social, interactive processes, which involve both superordinate states and subordinate ones. Nevertheless, as a result of their unequal power, subordinate state agency is typically expressed when subordinate states operate in conjunction with superordinate ones, a finding that poses empirical challenges for studying subordinate statesâ€™ ideas and their order-shaping role. To resolve this challenge, the paper explores how a pair of superordinate and subordinate states â€“ the United States and the Republic of China â€“ operated in conjunction with one another to shape the transition to a post-WWII order at Bretton Woods. It examines cases of idea convergence and divergence between the United States and China; carefully disentangles the conscious and unconscious drivers of idea convergence; and highlights three distinct mechanisms - amplifying, grafting and resistance by appropriation - through which subordinate states shape a changing order's shared ideas.