Democratic Sen. Tom Carper of Delaware announced Monday that he will not seek reelection to a fifth term in the U.S. Senate. Carper's announcement paves the way for a wide-open contest for the seat he has held since 2001 in heavily-blue Delaware. It also ensures that his unblemished record of never having lost an election during more than four decades in politics remains intact. (May 22) (AP video: Tassanee Vejpongsa)
