Arlen Specter Announces He Will Become a Democrat

Politico.com: Specter to switch to Democratic party, by Martin Kady II & John Bresnahan:

Republican Sen. Arlen Specter has decided to switch parties and become a Democrat, stunning his GOP colleagues in the Senate while pushing Democrats and President Barack Obama one step closer to unfettered power in Washington. 

Specter had been in secret talks with Senate Democratic leaders for months, according to Senate sources, but his final move to become a Democrat came after a recent poll showed him badly losing a Pennsylvania Republican primary next year. Specter talked with Obama Tuesday morning, and the president said he was "thrilled" to have Specter joining the Democratic side of the aisle. According to White House aides, Obama was handed a note by an aide that read: "Specter is announcing he is changing parties."