Recent political developments, such as the rise of populism and illiberal democracy, have challenged the longstanding and widespread commitment of some states to the rules-based international order. This so-called ‘backlash’ against international law and institutions impacts all spheres of international cooperation including peace and security, human rights, trade and finance, and the environment. This article examines the implications of such a backlash. It argues that, while it is tempting to view the backlash as a new phenomenon, the greater challenge is to identify what is distinct about this moment. It explores three ways states may respond, considering ramifications for future efforts to build and promote peaceful and cooperative international relations.