Heidegger’s ontological account of affectivity provides an interesting angle to consider questions of politics. On the one hand, one might take some of what Heidegger wrote on affectivity in the late 1920s and early 1930s—usually couched in the idiom of Stimmungen (moods) and Befindlichkeit—as a foreshadowing of his involvement with Nazi politics, culminating in his time as Führer-Rektor of Freiburg University (1933/34). On the other hand, Heidegger’s views on affectivity might be taken as a starting point for an ontological perspective on the political as such. His perspective on Befindlichkeit as disclosive postures can prepare such a reading, while especially his views on the ontological character of anxiety and boredom lead into the founding dimension of the political as such. This is because these affective orientations reveal the ungroundedness and thus radical contingency of existence. The flip side of this ungroundedness is the inevitability for self-determination—in other words: the need for deciding the undecidable. Although Heidegger’s own politics—at least in the early 1930s—did not explicitly relate to the affectively disclosed ungroundedness of existence, but rather curtailed this openness and indeterminacy in an individualistic and decisionistic closure, we argue that Heidegger’s view yields to a radically political reading. Not least, this is evidenced in much of French political thought since the 1960s which heavily draws on Heidegger’s ontological difference (see Marchart 2007). The political as such does not refer to politics as a sub-system of society, but to the questioning of the foundations of politics, which turn out to be necessarily “contingent foundations” (Butler 1992). It is our aim to trace this line of thought back to its origins in Heidegger’s works, in order to assess the potentials and pitfalls of ‘Heidegger on politics’.