The guilt of Nazi war criminal, Adolf Eichmann, has long been settled. However, during the trial and for years after, Hannah Arendt questioned the legal theories upon which the Jerusalem court relied. Part 1 of this article discusses how Arendt was uncertain about the use of precedent to judge unprecedented acts. Part 2 concerns the logic of proving Eichmann's culpable mental state when he came from a culture where morality had been turned on its head. Part 3 reveals Arendt's struggle with the rationale for universal jurisdiction as well as her unconventional understanding of 'territory'. Part 4 deals with Arendt's views on group affiliation and how those views informed her definition of 'genocide'. Finally, Part 5 details Arendt's most famous writings on "the banality of evil" and how Eichmann was found guilty, not for succumbing to immoral temptation or being a depraved deviant, but instead for conscientiously observing the flawed mores of the Third Reich. While Arendt ultimately supported Eichmann's conviction, her concerns surrounding the trial raise questions that are still relevant today.