Key Republican U.S. senators believe Pennsylvania’s 2010 race is now Arlen’s to lose.

From Politico:

Still stunned by Arlen Specter’s party switch, Republican senators are pessimistic about the chances for conservative GOP hopeful Pat Toomey in the Pennsylvania Senate race. “I don’t think there is anybody in the world who believes he can get elected senator there,” said Sen. Orrin Hatch, the vice chairman of the National Republican Senatorial Committee.  Asked if the NRSC would back Toomey, Hatch said, “I don’t think so” and that the party should look for “someone who can win there.”