Abstract: “Militant democracy” refers to the idea that, under certain circumstances, democracies have to adopt measures against individual citizens/political organizations who threaten to undermine or outright destroy democracy, but who do not engage in violent or other forms of criminal activity. While the idea remains controversial, there are many constitutional theorists who concede at least some role for militant democracy in fragile democracies; moreover, there is now a relatively clear sense of what the repertoire of militant democratic measures in constitutional law consists of (even if, again, many of the individual elements in that repertoire remain contested). My contribution asks whether elements of that repertoire could and should be applied at a supranational level. In other words: should international organizations have a role in defending the democracy of their members? The question sits at the intersection for normative political theory (there are obvious objections on the basis of ideals of self-determination, as well as duties to protect particular “constitutional identities”, comparative politics (what kind of measures might actually help to avert slides to authoritarianism?) and, above all, comparative constitutional law. The contribution will specifically examine the case of the EU, as it constitutes the most closely integrated international organization, but the cautious endorsement of a notion of a self-limiting supranational militant democracy can also be applied to other contexts (Latin America and Africa in particular).