William J. Brennan Jr.

Associate Justice from 1956 to 1990 who wrote landmark First and Fourteenth Amendment opinions. Brennan authored New York Times Co. v. Sullivan (1964), establishing that public officials must prove "actual malice" to win defamation suits, and Baker v. Carr (1962), requiring one-person-one-vote apportionment. He was perhaps the most influential liberal justice of the twentieth century.