Potter Stewart (January 23, 1915 – December 7, 1985) was an American lawyer and judge who was an associate justice of the United States Supreme Court from 1958 to 1981.

During his tenure, he made major contributions to criminal justice reform, civil rights, access to the courts, and Fourth Amendment jurisprudence.

[2] After graduating from Yale Law School in 1941, Stewart served in World War II as a member of the United States Navy Reserve.

Stewart wrote the majority opinion in cases such as Jones v. Alfred H. Mayer Co., Katz v. United States, Chimel v. California, and Sierra Club v. Morton.

He popularized the phrase "I know it when I see it" with a concurring opinion in Jacobellis v. Ohio, in which a theater owner had been fined for showing a supposedly obscene film.

Other members of that era included Gerald R. Ford, Peter H. Dominick, Walter Lord, William Scranton, R. Sargent Shriver, Cyrus R. Vance, and Byron R. White.

[5][6] In 1943, he married Mary Ann Bertles in a ceremony at Bruton Episcopal Church in Williamsburg, Virginia (at which his brother Zeph—also an initiate of Delta Kappa Epsilon and Skull and Bones, and eventually a professor of classics at Harvard—was the best man).

Stewart was nominated by President Dwight D. Eisenhower on April 6, 1954, to a seat on the United States Court of Appeals for the Sixth Circuit vacated by Judge Xenophon Hicks.

[7] Stewart received a recess appointment from President Eisenhower as an associate justice on the U.S. Supreme Court on October 14, 1958,[8] to succeed Harold Hitz Burton.

[13][14][15] A case early in his Supreme Court career showing his role as the swing vote during that time is Irvin v. Dowd.

Before the appointment of Warren Burger as Chief Justice, many speculated that President Richard Nixon would elevate Stewart to the post, some going so far as to call him the front-runner.

"[25] Before 1967, Fourth Amendment protections were mostly limited to notions of property: possessory geographical locations such as apartments or physical objects.

[26] The Katz case made government wiretapping by both state and federal authorities subject to the Fourth Amendment's warrant requirements.

[30] Stewart wrote the Court's opinions in Sierra Club v. Morton (1972) and United States v. SCRAP (1973), broadly laying out the requirements of standing in federal actions.

[30] In Jones v. Alfred H. Mayer Co. (1968), Stewart extended the 1866 Civil Rights Act to outlaw private refusals to buy, sell, or lease real or personal property for racially-discriminatory reasons.

[32] In Shuttlesworth v. City of Birmingham (1965), Stewart held for the Court that police could not use an anti-loitering law to keep civil rights workers from standing or demonstrating on a sidewalk.

"[33] Stewart authored the concurring opinions for two very controversial cases concerning public education: San Antonio Independent School District v. Rodriguez and Milliken v. Bradley.

[9] President Ronald Reagan nominated Sandra Day O'Connor to succeed Stewart; she would become the first woman to serve on the Supreme Court.

[41] Most of Stewart's personal and official papers are archived at the manuscript Yale University Library in New Haven, Connecticut, where they are now available for research.