For years, Pennsylvania Sen. Arlen Specter was organized labor’s best friend in the Republican Conference. But now that the state’s senior Senator is a Democrat, local union leaders said his record might not pass muster in a 2010 primary.

Rep. Joe Sestak’s (D) expected entrance into the Senate race would create a tough choice for labor unions in the state because the two-term Congressman would be a sure vote for their most important piece of legislation, the Employee Free Choice Act.

Before he switched parties, Specter said in a March floor statement that he intended to vote against cloture on EFCA — a reversal from his 2007 vote that effectively killed the legislation in its current state. Local labor leaders were not happy with Specter, who at the time was planning to run in a competitive GOP primary against former Rep. Pat Toomey. According to several labor organizers in Pennsylvania, Specter got an earful from union leaders when he returned to the state during the April recess.

Pennsylvania AFL-CIO President Bill George, a longtime ally of Specter’s, has seen his organization support the Senator in his last three re-election campaigns. But this time around, George was hesitant to predict whether the AFL-CIO would back Specter in 2010.

“He did give us the vote two years ago, and our rank and file don’t know why he can’t give us the vote now, when it’s exactly the same bill,— George said. “And I can’t explain it to our members.—

The AFL-CIO, with 900,000 members, is the most powerful union in the state, and the vast majority of its ranks are Democrats. Specter earned a 61 percent lifetime voting record from the national AFL-CIO, while Sestak earned a 96 percent rating.

“I think labor is frustrated with [Specter] right now,— former Rep. Joe Hoeffel (D-Pa.) said. “But if he opposes that bill and Congressman Sestak votes for it, I think that will probably determine who labor supports.—

Hoeffel, who supports Sestak, lost to Specter in the 2004 Senate race. In their statewide matchup five years ago, most labor organizations backed Specter.

“People knew I had a better voting record in terms of percentage than Sen. Specter, but he was their best supporter in the Republican Party, and that was important to them,— Hoeffel said.

Specter’s track record with organized labor hasn’t stopped Sestak from reaching out to unions in his district or in southeastern Pennsylvania.

In his official capacity, Sestak said, he formed a advisory group of about two dozen local union leaders who have met every few months since he was first elected. Sestak also said that while House Majority Leader Steny Hoyer (D-Md.) was going to recommend him for the Intelligence and Armed Services committees, he requested a spot on the Education and Labor Committee when he came to Congress in 2006.

Outside of his official capacity, Sestak said he has made “courtesy calls— to local and national labor leaders, including what he described as a recent positive meeting with national AFL-CIO President John Sweeney.

“But I do find, as I walk around, there are unions that may potentially … be very supportive of someone who has a stronger labor record, even outside of card check,— Sestak said in a phone interview Tuesday.

Pennsylvania Democratic Party Chairman T.J. Rooney said he has Specter’s personal assurance that he is working every day with his colleagues to develop some compromise language for EFCA. After all, Rooney pointed out, Specter isn’t the only Democrat who has said he is inclined to vote against the current version of EFCA.

“I know firsthand from Sen. Specter that he has been working daily over the past few weeks to come to compromise language to be able to get 60 votes to survive a filibuster,— Rooney said. “I can’t think of anybody better to bring about a resolution, especially among other Senators who have concerns.—

And while the Senator works on a compromise, labor leaders in Pennsylvania will watch the former Republican whom they once considered an ally across the aisle. Specter has had long relationships with several union officials in high-ranking posts in Pennsylvania and at the national level.

National AFL-CIO Secretary-Treasurer Rich Trumka, who is from the Keystone State and is particularly close to Specter, has publicly said that labor is not inclined to support the Senator if he does not back EFCA.

With 100,000 members, the Pennsylvania chapter of the Service Employees International Union is considered by many to be the second-most-prominent union organization in the state.

Executive Director Eileen Connelly said the state SEIU supported Specter in 2004 but not in 1998. An eight-member board will decide whether to endorse Specter for re-election or stay out of the primary in 2010.

Connelly was hesitant about whether her organization would endorse a candidate in the 2010 Senate primary or stay out of the race, but added that little had changed in the union’s relations with Specter since he declared he was a Democrat.

“Really, there’s been nothing different with respect to our relationship to Sen. Specter since he changed parties,— Connelly said.

SEIU President Andy Stern has met with Sestak and Specter as part of his regular legislative meetings.

In addition to the AFL-CIO and the SEIU, support from the teacher’s unions and the American Federation of State, County and Municipal Employees is important in the Democratic primary. The Pennsylvania State Education Association, an affiliate of the National Education Association, supported Specter in his 2004 race.

Sestak said he could see why labor unions in Pennsylvania would choose to back their longtime ally Specter, even though he said he has a stronger voting record for organized labor groups.

“I also think that there are some unions locally that go back in a long way with Arlen, and that’s very understandable,— Sestak said.

If Sestak runs, he would have a great deal of ground to make up compared with Specter’s long ties to leaders in the state. George said Sestak is relatively unknown statewide, adding that he has not heard from the Congressman yet about the race.

“Sestak has not called me and announced to me that he’s running for U.S. Senate, nor has he asked me for any endorsement,— George said.