Since Jacques Derrida''s 1989 essay "Force of Law: the Mystical Foundations of Authority," Carl Schmitt has been a perennial subject of Derrida''s political critique. I will argue that Derrida''s concept of auto-immunity is uniquely applicable to Derrida''s interpretation of Schmitt''s political philosophy. Derrida is a philosopher of a thousand faces. Perhaps, his last face was his concept of auto-immunity. Derrida begins to utilize this biological concept as early as the 1990s, but only after the terrorist attacks of September 11th does this concept becomes a predominate schema in which Derrida configures his philosophy. Derrida''s schema of auto-immunity also has a thousand faces. In many ways, this is the final concept of an illustrious history of prior concepts. Indeed, auto-immunity is deconstruction. As Michael Naas puts it: "Undecideability, aporia, antinomy, double bind: autoimmunity is explicitly inscribed in Rogues into a veritable ‘best of collection'' of Derrideo-phemes or deconstructo-nyms" (Naas, p. 29). I will exhibit how this schema uniquely applies to Derrida''s account of Carl Schmitt''s political philosophy as early as "Force of Law" and The Politics of Friendship.