In post-Soviet Russian politics, Boris Nemtsov is one of the most tragic figures—and not only because he was shot dead, at the age of 56, in close vicinity to the Kremlin, the locus of Russia’s power. The “transparency of evil” in this specific case was shocking: Nemtsov’s murder was filmed by a surveillance camera. The video tape confirms the demonstrative and insolent character of the assassination. His death illuminated a core feature of the current regime that tolerates, if not incites...