Delaware has a single at-large representative in the House of Representatives. Republican incumbent Mike Castle was reelected for an eighth term. As of 2025, this is the last time where a Republican won a congressional race in Delaware, and the last statewide race where the Republican won New Castle County. It was an impressive display of ticket-splitting by Delaware voters, as Castle, a Republican, obtained over 60% of the vote, while the Democratic candidates in the concurrent presidential, Senate, and gubernatorial elections all received over 60% of the vote as well.
The state of Delaware is completely contained in a single at-large district. The district had a Cook Partisan Voting Index of D+7 in 2008.[2] Since 1993, the district had been represented by RepublicanMike Castle.
Primary election
Primary elections in Delaware are closed primaries; that is, only voters who have declared a party affiliation may vote in that party's primary.[3] Three Democrats were on the primary ballot: children's rights advocate and 2006 independent candidate Karen Hartley-Nagle, veterinarian and Vietnam War veteran Jerry Northington, and Michael Miller.[4][5] Hartley-Nagle was nominated with 55.4 percent of the vote, with turnout at 28 percent.[6] Castle did not face any Republican primary challengers.
Democratic primary for the 2008 Delaware House of Representatives election[6]
In the general election, Republican incumbent Mike Castle was challenged by Democratic nominee Karen Hartley-Nagle and Libertarian Party candidate Mark Anthony Parks. CQ Politics forecasted the race in Delaware's at-large congressional district as 'Safe Republican'. Castle enjoyed a lead throughout the campaign, and ultimately won the election with slightly over 61 percent of the votes cast. Statewide turnout for the election was at 68 percent.[7]
2008 Delaware's at-large congressional district election[7]
