How should political leaders address the emerging climate crisis if citizens are reluctant to accept costly but necessary climate action? In this article, I address this question by harnessing insights from the realist tradition in political theory. I propose that the realist legitimacy framework provides action guidance by offering two broadly applicable heuristics for political agents: responsibility and responsiveness. These heuristics collide if citizens are unwilling to accept policies designed to secure a nation's long-term stability. Faced with this problem, some (...) authors make the supposedly realist argument that policymakers in liberal democracies should prioritise responsibility over responsiveness and embrace eco-authoritarianism to address the climate emergency. Against this line of argument, I maintain that the realist legitimacy framework entails no such commitment. Instead, realists must emphasise that responsible climate action entails a sufficient degree of responsiveness. I conclude by sketching how this insight may guide democratic leaders and climate activists in the future. (shrink)