With each new report of the Intergovernmental Panel on Climate Change, the urgency to address climate change seems to increase. As the pressure to act rises, debates are intensifying regarding whether democracies can move toward sustainability fast enough. In this introduction to the special issue, we argue that current debates about the democracy–sustainability nexus revolve around the question of who should decide. Much of the recent debate can be structured along three opposites: experts versus laypersons, less versus more participation, and state versus market/private actor solutions. The first distinction asks whether climate change necessitates a shift of decision-making powers to scientists and experts rather than politicians or citizens. In the second debate, those who favor more participation in environmental policymaking face those who demand less. For example, whereas some promote new forms of deliberative forums, others doubt that these can be effective. Finally, there is a debate on whether markets and private actor networks might provide more efficient and effective ways to deal with the climate crisis than state regulation. While these perspectives are highly diverse and even contradictory, they are united in the belief that standard procedures of liberal democracy are insufficient to achieve sustainability.