It is well-known that democracy's enemies could rely on the democratic right to free speech to destroy democracy itself. The classic dilemma to be solved, then, is the question whether democracy could defend itself against hostile speech in a way, which would not also endanger the right that forms its own political heart. What makes the resolution of this dilemma such an arduous task is the principle of consent, which has traditionally constituted democracy's source of legitimacy. This principle is precisely what forms the theoretical Achilles' heel in democracy's self-defense as well, should enemies of this political system choose to pursue its destruction by means of the ballot box. Under that scenario, they would rely on democratic liberties in general, and the right to free speech in particular, to conquer power through the process of majority formation, and subsequently proceed to abolish the process that has made possible their conquest of power in the first place. If democratic government, however, seeks to neutralize this threat by restricting or suspending the democratic rights of democracy's enemies, then it would expose itself to the allegation of betraying the very principle, which constitutes the source of its legitimacy. Democracy's enemies could, after all, credibly allege that laws which are specifically enacted to deprive them of the rights to democratic participation cannot somehow be rooted in their own consent, whereas consent is a sine qua non for the democratic legitimacy of a law. The first challenge to be addressed, therefore, is whether democracy may be able to defend itself against hostile speech in a selfconsistent way. Related to this is the challenge of how to prevent democracy's efforts at selfdefense from degenerating into a suppression of political dissent in general. Would it be possible for a democratic government to combat extremist speech without endangering the right to free speech itself? This second challenge is one that we have to face whenever a democratic government feels compelled to take measures to defend itself against its enemies. As Susanne Baer has pointed out, “a state engaged in self-defence tends to go too far.” Drawing on a theory of democracy elaborated by Hans Kelsen under the Weimar Republic, we shall argue in this Article that it is entirely possible for a democratic regime to both suppress the expression of antidemocratic ideas and preserve freedom of speech at the same time.