Pennsylvania Sen. Arlen Specter will switch parties and run for reelection in November 2010 as a Democrat, he announced today, a decision that could have wide-ranging consequences for the Senate and President Obama's agenda. Specter told reporters that he received a "bleak" poll Friday from his advisers that showed virtually no chance of him winning in the GOP primary next spring against Pat Toomey, a former Republican House member who recently led the conservative Club for Growth. He said that the loss of several hundred thousand GOP voters who left the party in 2008 to vote in the Democratic presidential...