HARRISBURG, Pa. (AP) - Twenty-nine years into his U.S. Senate career, Arlen Specter cast what he calls his most difficult vote - a "yes" on the $787 billion economic stimulus bill that made him the only Republican facing re-election in 2010 to support it.
Now, with GOP anger still simmering, Specter is under pressure to buck the party again and support "card check" legislation to make it easier for workers to form unions.
It is the latest tight spot for the 79-year-old Specter, a moderate and maverick who is used to being on the political rack, stretched between the wishes of an increasingly conservative party and an increasingly liberal state.
He is in meetings every day about the card check bill, he said, but isn't revealing to anybody which way he is leaning.
"I've been in this line of work long enough that people ... know my arm's not twistable," Specter said in an interview Thursday with The Associated Press.
It is that streak of independence that the fifth-term Specter flaunts and Republicans fear.
Republicans appear to be otherwise unified against the card check bill, which is expected to surface later this year. They worry that Specter could exert influence over its final form and whether it comes up for a vote, as he did on the stimulus.
"I think he again could be the swing vote on the issue," said Bill Darr, chairman of the Pennsylvania Republican Party's 11-county southwest caucus.
The stimulus won support from no House Republicans and just two other Republican senators: Maine's Olympia Snowe and Susan Collins.
Many Pennsylvania party elders have been unwilling to criticize Specter and have not forsworn him as the party's candidate in 2010.
Yet they are not endorsing him enthusiastically, either.
Pennsylvania's GOP chairman, Robert Gleason, would not say whether he will work against Specter's candidacy in the 2010 primary, or whether Specter must vote against the card check bill to win the endorsement.
"It's pretty far away," Gleason said. "A day is a lifetime in politics."
Michael Steele, the Republican National Committee chairman, said in television interviews last week that he would follow the state party if it chooses to back a primary challenger to Specter. The National Republican Senatorial Committee, chaired by conservative Sen. John Cornyn of Texas, "unequivocally supports Senator Specter and will do anything we can to get him re-elected," spokeswoman Amber Wilkerson said.
So far, no Republican challenger to Specter has emerged, although conservatives, who came within 17,000 votes of knocking off Specter in the 2004 GOP primary, say they will run a candidate in the primary.
The only declared Democratic candidate - Philadelphia civic leader Joe Torsella - is a virtual unknown in statewide politics.
In 2004, Specter beat Democratic U.S. Rep. Joe Hoeffel by 590,000 votes. Now, thanks to heavy Democratic voter recruitment during the presidential campaign last year, the Democratic registration edge has more than doubled to 1.2 million.
For now, Specter holds outsized influence thanks to the new 58-member Senate majority won by Democrats in November's election. Senate Democrats see Specter as a crucial stepping stone for reaching the 60 votes necessary to force debate or a vote on legislation in the chamber. A bill requires a simple majority to pass.
At a reception Friday in Philadelphia with Pennsylvania's congressional delegation, Vice President Joe Biden thanked Specter for supporting the stimulus bill.
"He knows what's worth losing over and he's willing to act on it," Biden said. "In his heart, I know he's a Democrat."
The card check legislation could be a defining issue for Specter's reputation: It is a top priority for labor unions and has solid opposition from business groups, which were divided over the stimulus bill.
"I think the vote for the stimulus will pale in comparison to the card check," said G. Terry Madonna, director of the Center for Opinion Research at Franklin & Marshall College in Lancaster.
In 2007, the card check bill passed the House with only 13 Republicans supporting it. In the Senate, Specter was the only Republican to vote with Democrats to force debate on the legislation, even though the bill had insufficient votes to advance and President George Bush had promised to veto it.
Unions view Specter as a better friend than just about any other Republican senator - the state's AFL-CIO even endorsed him over Hoeffel in 2004. He has voted for trade bills that benefit the steel industry, a minimum wage increase and expanded funding for children's health insurance.
But a vote against the card check bill would almost surely turn unions against Specter next year, warned Bill George, president of the AFL-CIO in Pennsylvania.
Specter said he always has voted with his conscience, even if it conflicts with his party's goals, and will do so again. He recently recounted how a fellow Republican senator complimented him after he
helped broker an agreement on the stimulus bill.
"I said `Well, will you vote with me?' He said `No I couldn't do that, it might bring me a primary contest,"' Specter told reporters. "I said `Well, you know it's going to bring me a primary contest."'
(Copyright 2009 by The Associated Press. All Rights Reserved.)