Wayne Morse (October 20, 1900 - July 22, 1974) was a United States Senator from Oregon from 1945 to 1969. He made a filibuster for 22 hours and 26 minutes in 1953 protesting the Tidelands Oil legislation .

Morse was born to a farming family in Verona, Wisconsin, who imbued the political beliefs of Robert M. LaFollette, Sr. in their children. He received his Bachelor's degree from the University of Wisconsin in 1923, and his Master's from the same college the next year. He received his degree in law from the University of Minnesota in 1928, and became an assistant professor of law at the University of Oregon in 1930.

Described as an electrifying speaker and having a brilliant legal mind, he quickly became an associate professor and then dean of the university and full professor of law in 1931. Columbia University awarded him a doctorate in law in 1932. He served on many public commissions over following years.

In 1944 he won the Republican primary election for Senator, and the general election that November. Once in Washington, he revealed his progressive roots to the consternation of his more conservative Republican peers. In protest to Dwight Eisenhower's selection of Richard Nixon as his running mate, he left the Republican party in 1952. After a term as an independent, he became a Senator for the Democratic Party in 1955. Despite these switches in party allegiance, for which he was branded a maverick, Morse won almost every election for Senator.

In 1964, he was one of only two Senators to vote against the Gulf of Tonkin Resolution (Alaska senator Ernest Gruening was the other), which authorized further United States involvement in the Vietnam War. Partially as a result, Morse lost his seat in the 1968 election to Bob Packwood by 3,000 votes.

Morse spent the remaining years of his life attempting to regain his seat. He was the Democratic nominee for the Senate in 1972 but lost to incumbent Mark Hatfield. He won his party's primary again two years later, setting up a return match against Packwood, but died before the general election.