The article seeks to explain why spontaneity, a concept that political theorists have given scant attention to, matters. It argues that it matters because it delivers a capacity for producing democratic change that is urgent to reflect on amidst a prevailing mood of grief over a democracy lost. To stimulate this reflection, the article engages with Rosa Luxemburg’s work, showing how her understanding of spontaneity as an initiative that delivers something for democracy lays the groundwork for a theoretical orientation that (...) allows us to notice the effects of spontaneity on democracy without overplaying its short-lived nature. (shrink)