This article makes use of primary sources to reconstruct Carl Schmitt's engagement with the work of Hannah Arendt. It focuses on Eichmann in Jerusalem (1963): a book that Schmitt called “exciting” and that made him sick “for a couple of weeks.” The article examines marginalia to explore the reasons behind this ambiguous reaction. It situates Schmitt's reading of Arendt in the aftermath of his 1945 defense writings in which he had come close to legitimizing the international criminal prosecution of Nazi officials: a position he feared could backfire against himself in light of the Eichmann trial. Despite points of agreement in their critiques of depoliticized legality, Schmitt's reading of Arendt remained limited by anti-Semitic hatred and his fear of persecution. Driven by a sense of antagonism rather than dialogue, Schmitt's meticulous Arendt collection reveals above all that he turned to her work in search of theoretical weapons of self-defense.