Arlen Specter, the Republican-turned-Democrat now running for re-election, has received the endorsement of the Pennsylvania AFL-CIO in his primary campaign against Democratic Rep. Joe Sestak.

Specter has received plenty of labor endorsements before, even when he ran as a Republican (they backed him in 2004 over Democrat Joe Hoeffel). But considering that Specter vocally opposed the Employee Free Choice Act last year, his return to the good graces of labor is a bit surprising. Specter had to win over 2/3 of the members present at the state federation meeting.

“In our opinion Senator Arlen Specter is the strongest advocate and supporter for good jobs, fair trade policies, workers’ rights and quality affordable health care for all,” said Bill George, president of the umbrella group, which represents 900,000 workers statewide.

“He is a proven leader who has stood with working families when the chips are down, especially his key role in passing the American Recovery and Reinvestment of 2009 which has protected jobs, helped unemployed workers, and prevented this nation from sinking into another great depression,” George said.

Of course, in exchange for that stimulus vote, Specter removed $100 billion dollars in mainly state fiscal aid, leading to larger budget gaps and more state employee layoffs, including those who are part of AFSCME, a member of the AFL-CIO coalition. But apparently, that’s water under the bridge.

Sestak has lost most of the major labor endorsements to Specter in this primary, as well as the Democratic State Committee. He has not caught fire in any polling, and he only has a month and a half to do so. The labor endorsement of Specter makes Sestak’s task even more difficult.