Muskie, Edmund Sixtus (1914-1996), a Maine Democrat, served in the U.S. Senate from 1959 to 1980. He was the first Democrat ever elected to the U.S. Senate by Maine voters. He was the Democratic nominee for Vice President of the United States in 1968. He and presidential candidate Hubert H. Humphrey were defeated by their Republican opponents, Richard M. Nixon and Spiro T. Agnew. In 1980 and 1981, Muskie served as secretary of state under President Jimmy Carter.