Michael Newbold Castle (born July 2, 1939) is an American attorney and politician who was governor of Delaware (1985–92) and the U.S. Representative for Delaware's at-large congressional district (1993–2011). He is a member of the Republican Party. The district includes the entire state of Delaware and is the oldest intact surviving district in the nation. He was the longest-serving U.S. Representative in the state's history. Before his election to Congress, Castle served as a member of the Delaware General Assembly, starting in the State House of Representatives (1966–67) and then in the State Senate (1968–76). He was the 20th lieutenant governor of Delaware from 1981 to 1985, and the 69th governor of Delaware from 1985 to 1992. On October 6, 2009, Castle announced his candidacy in the 2010 special election for the seat in the United States Senate held by Democrat Ted Kaufman. Kaufman, appointed by Governor Ruth Ann Minner to fill the vacancy created by Joe Biden (who resigned to become Vice President of the United States), was not a candidate in the election. The election determined who would fill the balance of Biden's term, which ended on January 3, 2015. In one of the most surprising election results of 2010, Castle lost the Republican primary to Christine O'Donnell. He would have been heavily favored in the general election against Democrat Chris Coons, who defeated O'Donnell by 17 percentage points.Castle has acknowledged drafting the bill which became law and created the trillion-dollar coin controversy by apparently authorizing the United States Department of Treasury to mint platinum coinage in any denomination. He is a member of the ReFormers Caucus of Issue One.