Sen. Arlen Specter spent much of his career in Republican politics fending off attacks from a party base that viewed him as an outcast who did not embrace many of its core principals.
Now as a Democrat, the five-time senator is poised to once again walk the political tightrope, though this time the pressure will come from the left rather than the right.
Pennsylvania represents a key political battleground -- a state that has trended Democratic in recent elections but one where coal and manufacturing remain a key part of the economic base and Republicans believe it will swing back in their direction if the majority is seen as damaging those industries.
Nowhere was that dynamic more apparent than during the House vote on the cap-and-trade bill. Four Pennsylvania Democrats, most elected in the last two cycles in swing districts, voted against the legislation as did three moderate Republicans who were also viewed as potential "yes" votes but ultimately sided with their party leadership.
Specter has plenty of company in the Senate club of potential swing votes, but he is in the unique position of having to prove his Democratic bona fides to a base that has not completely warmed to him while keeping an eye on a potentially tough general election challenge.
Specter has already started to walk that fine line -- thus far refusing to explicitly back or oppose the Senate version of the bill while signaling to voters from both ends of the political spectrum that he is attuned to their concerns.
He has told liberal bloggers that at the very least he would oppose a filibuster on the legislation. But when Sens. John Kerry (D-Mass.) and Barbara Boxer (D-Calif.) unveiled their version of the bill last week, Specter withheld his support for the package, saying he would like to see several changes.
Over the next couple months, Pennsylvania observers say they expect Specter to handle the climate bill much as he has other issues -- using his political muscle as a key swing vote to extract as many concessions as he can from party leaders and then using the package to placate critics on both sides.
"Senator Specter is the master of declaring victory for anything he can get," said David Patti, president and CEO of the advocacy group Pennsylvania Business Council. "In terms of his campaign literature and media pieces, whether it will be a little bit or a lot of compromises on coal issues, he'll declare victory."
Pressure from the left
For Specter, the challenge is more daunting than simply trying to appease coal industry supporters and moderate voters in an election that is more than a year away. He is facing more immediate pressure from his left flank, where his main challenger is attempting to paint the lack of full support for the Kerry-Boxer bill as a key sign that the senator is not fully behind President Obama and the Democratic agenda.
Upon switching parties earlier this year, Specter openly admitted that he was doing so because it would give him the best chance of returning to Congress for another term. The White House quickly backed Specter as its Democratic candidate in the Pennsylvania Senate race and at least early on it appeared that Specter was well positioned to prevail in both the Democratic primary and the general election.
But portions of the Democratic base have yet to come around, and Specter now faces a vigorous primary challenge from two-term Rep. Joe Sestak.
Sestak has not been content to let the Senate climate debate play out and allow Specter to negotiate various provisions. Instead, Sestak is urging Specter to throw his support behind the legislation before December's U.N. climate talks in Copenhagen, Denmark.
"If you truly believe, as I do, in a job creating and economy sustaining clean energy future and that it is important for Pennsylvania and this Nation to send the world a clear message of support for President Obama's efforts to pass a comprehensive climate treaty in Copenhagen, I urge you to clearly state your support for the passage of effective climate change legislation by December," Sestak wrote in a letter to Specter last week.
Sestak, who voted for the House measure, went on to criticize Specter for opposing "green energy reform" both as a Republican and since he switched parties, pointing to Specter's criticism of the House-passed bill.
With the Senate potentially not taking up the climate bill until early 2010, Senate consideration of the measure could overlap with the run-up to the Democratic primary in May.
The criticism from Sestak comes as little surprise, according to pundits, as it potentially gives the challenger an opportunity to try to split Specter from the base on an issue that is extremely popular with core Democratic voters.
A Quinnipiac University poll released last week showed Specter holding a significant lead over Sestak, 44 percent to 25 percent.
"[Sestak] needs to build up a clear reason why he's a better Democrat than Arlen Specter, so on issues like this he's all aboard with cap-and-trade because it speaks to the Democratic base," said Christopher Borick, a Pennsylvanian politics expert at Muhlenberg College.
"Sestak undoubtedly has positioned himself on the left, unabashedly supporting policies like cap and trade and addressing climate change," Borick added.
When asked about Sestak's criticisms last week, Specter said that so far he has been feeling little pressure from the Democratic base to support the Kerry-Boxer bill and instead pivoted to what has been a common theme for his campaign -- attacking Sestak for the votes he has missed in the House this year.
"It's very hard for me to understand what he's doing," Specter said. "But I think that it's just curious that he would ask me for my position when the voters of the 7th District are trying to find out what his position is on 122 votes."
Indeed, Specter responded to Sestak's letter with one of his own that criticized the lawmaker for the missed votes but also included a climate change policy white paper that outlines Specter's history of supporting policies to address climate change. One of those items was Specter's co-sponsorship in 2007 of a cap-and-trade bill backed by Senate Energy and Natural Resources Chairman Jeff Bingaman (D-N.M.) and a handful of moderate lawmakers from both parties.
While most environmentalists viewed the bill as being far weaker than the legislation crafted by Boxer and other Democratic leaders, Specter nonetheless was one of the few congressional Republicans to attach his name to a climate change bill.
Specter, however, has yet to endorse the Kerry-Boxer bill, saying that he believed the bill could be structured in a way that is "economically responsible" and "environmentally effective" but also saying that it needed a number of modifications. Among them: the inclusion of a price collar guaranteeing more price certainty than the House version, a combination of incentives and payments to ensure commercial deployment of carbon capture technology, and the inclusion of adequate allowances to protect energy-intensive manufacturing.
Similar demands have been made by a number of Democratic senators, and observers say they expect Specter to eventually back the bill -- assuming he gets some of those concessions.
"I think both [Specter and Sen. Bob Casey (D-Pa.)] recognize the need to act on global warming and clean energy," said Nathan Wilcox, energy and clean air advocate at the environmental group PennEnvironment. "I think their only hesitation is that they are trying to see what they can do to protect the coal industry as much as possible in Pennsylvania, while at the same time passing a bill at the end."
While it is likely that environmental groups and Sestak will continue to lean on Specter to support the bill for as long as the Senate debate drags out, Borick noted that Democratic voters may give the senator some leeway in dealing with the legislation.
"Specter has never been a villain of Democratic voters on environmental policy ... but he does have some work to do," Borick said.
Borick added that while on some level Democratic voters may recognize that Specter may not pass every item on their litmus test, it may not matter if they think he can win in November.
"In recent history, you've seen that Pennsylvania Democratic voters have become more interested in winning than they once were and they're willing to make concessions," Borick said.
Fiercest challenge may come in general election
If polls are to be believed, Specter's biggest challenge may not come in the primary but in the general election, where the cap-and-trade issues are likely to again bubble to the surface.
The same Quinnipiac poll that showed Specter with a large lead on Sestak, showed him trailing former Republican Rep. Pat Toomey, the likely GOP nominee, by a margin of 43 percent to 42 percent. That represents a dramatic reversal from a May poll, conducted immediately after Specter switched parties, which showed him with a 20 percentage point lead.
Toomey, who narrowly lost the GOP Senate primary to Specter in 2004, last week blasted both Specter and Sestak for voicing support for the Democrats' climate change legislation, describing it as a product of "extreme policies resulting from one-party rule."
Toomey said, "I urge the senator to consider the impact of such an extreme bill would have on Pennsylvania's economy and reject the extremism of the Democratic Party's left wing."
Such attacks from Toomey are likely to intensify on whichever candidate emerges from the Democrats as Republicans zero in on Obama's dropping approval ratings as an opportunity to score a major victory in a state that has trended away from them in recent years.
"I think for Toomey and some Republicans -- they think they can lump cap and trade in with economic stimulus plan and whatever emerges in health care as part and parcel with an intrusive expanding government narrative that they want to play out in next year's election cycle," Borick said.
Environmentalists, meanwhile, say that while the coal industry still plays a prominent role in pockets of the state, it no longer has the influence that it once did and voters are more eager to back "clean energy" policies.
"Yes there are pockets that are very conservative and will oppose this legislation, but it's also true that the majority of the Pennsylvania populations is in the cities and suburbs with much more moderate politics," said Wilcox of PennEnvironment.
Business advocates do not quite see it that way -- arguing that in politically key portions of the state, concern about the future of the coal industry continues to run deep.
"In western Pennsylvania, the coal workers, for them they get this, for them this jobs," said Patti of the Pennsylvania Business Council. "Coal isn't king, but I also wouldn't be wholly dismissive."
Environmentalists admit Specter will face pressure from the right to vote against a climate bill, but they point out that they still prefer the current situation to the one staring them in the face a few months ago -- Specter running in a GOP primary and having to placate a party base that is distinctly against a cap-and-trade bill.
"I think he is in a better place than where he was on this issue -- it was no secret that running in a Republican primary he was going to have to swerve pretty hard to the right to win," Wilcox said.
Reporter Robin Bravender contributed.
Correction: An earlier version of this story incorrectly quoted Sen. Specter. He said that the Kerry-Boxer bill must be "economically responsible" and "environmentally effective."
Want to read more stories like this?
E&E is the leading source for comprehensive, daily coverage of environmental and energy politics and policy.
Click here to start a free trial to E&E -- the best way to track policy and markets.