Republican Pennsylvania Sen. Arlen Specter is planning to switch to the Democratic party in hopes of increasing his chances of winning another term next year. If Al Franken wins the continuing Minnesota battle for the open seat, it would give Democrats in the Senate a 60-vote filibuster-proof majority.
Specter, 79, has served five terms in the Senate. He is one of the few moderate Republicans remaining in Congress.
Read his full announcement here.