As of 2008, Democrats had controlled the Delaware governorship for 16 years. In an upset, state Treasurer Jack Markell defeated Lieutenant Governor John Carney by 51 to 49% for the Democratic nomination on September 9. The Republican nominee was former state Superior Court Judge William Swain "Bill" Lee, defeating airline pilot Michael Protrack. Lee was the Republican nominee for governor in 2004, and lost to Minner by a narrow margin.
The race received more attention with the potential elevation of U.S. Senator Joe Biden as Barack Obama's choice as his Vice President of the United States. Election of a Republican governor would assist the party by proxy gaining an additional seat in the US Senate but Lee was defeated by a wide margin by Markell. Senator Biden resigned his seat in the United States Senate on January 15, 2009, and Ted Kaufman was appointed by Governor Minner to the vacant seat. Kaufman had previously served as Senator Biden's Chief of Staff during his tenure in the United States Senate.