Methodological nationalism takes the nation‐state as a pre‐given container of social life, and thereby treats internal and international migrations as separate matters. Epistemological behaviouralism redresses this by removing the conceptual divide between internal and international but is problematic in regarding migration as a human behaviour distinct in itself. In explaining why and how these two pitfalls need to be addressed in tandem, I first trace how these contrasting viewpoints are historically deeply intertwined. I then draw on examples from China to demonstrate that migrations should be understood as composites of actions carried out by multiple actors and institutions, which in their turn lead to and become part of other social processes. Internal and international migrations are interlinked as constituted and constitutive assemblages. In the case of China, the nation‐state is a central link between the two, and is at the same time itself reconfigured by mobilities. Instead of promoting migration as a subject matter in its own right and migration studies as a distinct field, this article seeks to turn migration into an analytical perspective to examine broad social changes. Copyright © 2015 John Wiley & Sons, Ltd.