George John Mitchell Jr. is an American politician, diplomat, and lawyer. A leading member of the Democratic Party, he served as a United States senator from Maine from 1980 to 1995, and as Senate Majority Leader from 1989 to 1995. After retiring from the Senate, Mitchell played a leading role in negotiations for peace in Northern Ireland and the Middle East. He was appointed United States Special Envoy for Northern Ireland (1995–2001) by President Clinton and as United States Special Envoy for Middle East Peace (2009–2011) by President Barack Obama.

The positions of majority leader and minority leader are held by two United States senators and people of the party leadership of the United States Senate. They serve as a chief spokespersons for their respective political parties holding the majority and the minority in the United States Senate. They are each elected as majority leader and minority leader by the senators of their party caucuses: the Senate Democratic Caucus and the Senate Republican Conference.