Dr. Sidney Gottlieb

Sidney Gottlieb is the CIA's chief chemist, the quiet architect of MKUltra, the agency's covert program testing drugs and psychological manipulation on unwitting subjects. He speaks softly, dresses plainly, and carries himself like a mild-mannered scientist rather than a man authorizing experiments on human minds in the name of Cold War necessity.

Tim Blake Nelson plays him without villainy or flourish, which is the point: Gottlieb is frightening precisely because he seems reasonable, even gentle. Errol Morris's docudrama structure lets that stillness sit uncomfortably against the damage his work causes, and Nelson never tips his hand toward judgment, forcing the audience to do that work themselves.