The Pennsylvania branch of the Service Employees International Union announced Tuesday it’s backing Sen. Arlen Specter in the Democratic primary.

"He's been there for us and now we are proud to be here for him. We have close to 100,000 SEIU members in PA and we are ready to play our part in making sure Senator Specter stays in the U.S. Senate so he can keep working on behalf of Pennsylvania families," Eileen Connelly, the union's Pennsylvania executive director, said in a statement.

Specter said he was grateful to the "political powerhouse" for their endorsement and "their grassroots assistance."