PFEFFER, LEO (1910–1993), U.S. professor of constitutional law and constitutional lawyer. Pfeffer, who was born in Hungary, the son of an Orthodox rabbi, was taken to the U.S. in 1912. He studied law at New York University and practiced privately from 1933 to 1945, when he accepted a position on the legal staff of the Commission of Law and Social Action, the legal and political arm of the *American Jewish Congress. In 1947 he became assistant-director of the Commission and in 1957 its director, as well as general counsel of the American Jewish Congress. In 1964 Pfeffer became special counsel of the Congress. From 1965 to 1980, he became professor of constitutional law and chairman of the political science department at Long Island University. He co-founded the Lawyers Constitutional Defense Committee (which later became part of the American Civil Liberties Union), an organization formed to provide legal services in defense of civil rights.
A noted lecturer on constitutional issues, Pfeffer was recognized as a specialist in the area of church-state relations and religious liberty. He participated as counsel in numerous cases decided by the U.S. Supreme Court and other of the nation's appellate courts involving these issues. Pfeffer's writings include: Church, State and Freedom (19672); The Liberties of an American (19632); Creeds in Competition (1958; with Anson Phelps Stokes); Church and State in the U.S. (1964); and This Honourable Court (1965).