William Brennan, U.S. Supreme Court justice, was one of the architects of the constitutional revolution that radically changed American life in the second half of the twentieth century. As Chief Justice Earl Warren’s righthand man, Brennan was responsible for crafting majority opinions such as Baker v. Carr, which helped to establish the principle of “one person, one vote” and which Warren always referred to as the most important decision handed down during his momentous tenure on the Court. Brennan, whose politics placed him squarely at the Warren Court’s center, was also responsible for crafting majorities for opinions such as the one he wrote in New York Times Co. v. Sullivan, which managed to greatly expand the First Amendment while avoiding his more liberal colleagues’ wish to make criticism of public officials immune to libel suits. During the Warren years (1953–1969), Brennan was the justice least likely to dissent from the majority’s views; but later, during the tenures of Chief Justices Warren Burger and William Rehnquist, he frequently played the role of passionate dissenter, most notably in death penalty cases. Nonetheless, as late as a year before he retired from an increasingly conservative Court, Brennan marshaled a majority in Texas v. Johnson and engineered an opinion that expanded the definition of protected speech. It is no accident that Brennan is remembered not only for the law he made but also for his skills as a coalition builder.