We provide a very different way to think about how consensus may arise. We deliberately skimp on the micro-processes of persuasion usually emphasized in constructivist accounts, instead highlighting the structural aspects of the cross-national networks through which experts communicate with each other. Specifically, we treat the spread of ideas within the relevant community of experts as a process of contagion, similar in many respects to the spread of an infectious disease. We also examine how such processes may lead to expert dissensus as well as consensus, and how this affects the power of ideas. If ideational consensus plays a key role in underpinning global financial orders, then we need to understand how such consensuses are generated, maintained and challenged. If we wish to understand the current politics of non-consensus, we need to move beyond the existing literature to evaluate the consequences of dissensus for economic order. We provide an account that does both, and, more speculatively, draws general conclusions about the consequences of ideas for international economic orders.