Joe Biden held the Delaware Senate seat for more than 30 years before being elected Vice President in 2008.
Democrat Ted Kaufman, a longtime aide to Joe Biden, was appointed to fill the remainder of Biden's term.
Democrats widely assumed that Biden's son Beau would seek the Senate seat this year.
Dems are scrambling to find someone to challenge Republican Congressman Mike Castle, who is now the clear favorite on win the Delaware Senate race.
(Copyright 2010 by VERTEXNews/Newsroom Solutions)
Copyright 2015 Nexstar Broadcasting, Inc. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.