Formulated the "one person, one vote" standard. State elections must adhere to the "one person, one vote" principle. Decided March 18, 1963 (argued January 17, 1963). Opinion of the Court: William O. Douglas → go there Dissenting: Harlan. Applied: the Fourteenth Amendment → go there Topic: Voting and redistricting. Gray v. Sanders, 372 U.S. 368 (1963), was a Supreme Court of the United States case dealing with equal representation in regard to the American election system and formulated the famous "one person, one vote" standard applied in this case for "counting votes in a Democratic primary election for the nomination of a United States Senator and statewide officers — which was practically equivalent to election." Wiki link