"It is emphatically the province and duty of the judicial department," John Marshall wrote in Marbury v. Madison, "to say what the law is." As its Chief Justice from 1801 to 1835, Marshall made the Supreme Court a full and equal branch of the federal government. In so doing, he joined Washington, his mentor, and Jefferson, his ideological rival, in the first rank of American founders. His legacy extends far beyond Marbury, which held...