Akhil Reed Amar traces judicial review from its constitutional logic to its modern scale, in this Yale lecture from America's Written Constitution. He derives the principle in two steps, the Constitution's higher democratic pedigree and judges' duty to follow law, and notes that Congress and the president exercise parallel vetoes of their own. Amar shows how modest the founders' version was: an unspecified Court size, an original bench of six, no requirement for written or collective opinions, and a Marshall Court that struck down state laws constantly while invalidating only one federal statute before 1850. He explains the later expansion through more judges, certiorari and docket control, postwar rights amendments, and divided government. The lecture also treats juries as Article III's lower house, and closes with John Marshall, who made the Court politically real, and his successor Roger Taney, whose Dred Scott ruling reflected a pro-slavery vision.