Nations are regularly considered the main bearers of responsibility for climatechange. Accordingly, the differences between nations are crucial inunderstanding how responsibilities should be distributed. In this article, Iexamine the relevance of differences in type of political regime to this end.The claim defended here is that democratic institutions are constitutive ofthe conditions for when members of nations can be held responsible as acollective for the outcomes affecting the climate. The implications of thisaccount are demonstrated, first, in relation to claims of historicalresponsibility and, second, in relation to the burdens assigned to Annex Icountries by the UN Framework Convention on Climate Change. Theanalysis shows why democratic institutions – at present and in the past –are essential in order to conclude that the members of a nation shareresponsibility for the harm caused by the aggregate greenhouse emissions oftheir nation. In connection to this analysis, we also show why responsibilityfor the costs of climate change is also sometimes justly placed onauthoritarian nations.