After weeks of preoccupation with stimulus legislation now headed to President Barack Obama's desk, Pennsylvania lawmakers head into a still-new congressional session with varied but often overlapping agendas.

Even before the debate over the unprecedented rescue package, the new Congress and its bolstered Democratic majority appeared to be faced with an extraordinarily ambitious agenda.

In the coming months, Congress and the new administration hope to take action on complex and controversial issues, including health care, climate change, a new and costly transportation measure, and a review of the controversial No Child Left Behind legislation. Addressing them, Pennsylvania lawmakers bring different experience, priorities and degrees of clout.

The presidential election brought new attention to the state's junior senator, Bob Casey, through his support for and apparent friendship with the new president -- a bond with at least the potential to pay off for his own career and his state's legislative prospects. The stimulus debate revived a focus on Sen. Arlen Specter's often-pivotal role as political wild card.

In the House of Representatives, the state's members include a handful of veteran lawmakers, notably Rep. John Murtha, D-Johnstown, whose long tenure could afford key roles on specific issues. But in a body that places a premium on seniority, the Pennsylvania delegation's influence is at the same time constrained by a high degree of recent turnover among its members.

The last two election cycles brought new representatives to six of the state's 19 districts; five of the six were Democrats. After the last redistricting, the 2002 elections produced a 12-to-7 Republican majority in the state delegation. Rep. Kathy Dahlkemper's ouster of veteran Erie Republican Phil English last November, following the four-seat net gain for the Democrats in the party's 2006 Congressional landslide, completely reversed that ratio.

The 2006 landslide also launched the Senate career of Mr. Casey, who after a relatively low-key first two years, found a corner of the national spotlight as a basketball buddy of the new president. Mr. Casey takes pains not to exaggerate the tie.

He estimates that he's met personally with Mr. Obama roughly five times since they exchanged rebounds and congratulations on Election Day in Chicago. But he's unabashed in his hopes to capitalize on it for his state and his own policy goals.

"I don't know," he said, when asked how much impact the bond might promise. "It's uncharted waters in a sense for the state and for me and for anyone in my position. But I want to work assiduously to make sure it pays dividends for our state."

He pointed to the quick response he'd received last weekend when he called new Attorney General Eric Holder about an issue related to a string of arsons in suburban Philadelphia.

"I called him Saturday and talked to him within a half an hour of making that call -- that doesn't always happen."

Mr. Casey has a legacy interest in health care, one of the signature issues for his late father, former Gov. Bob Casey. He is optimistic that the White House priority will see significant progress, if not a final resolution this year.

"I'm not sure it's best to try to do it all in one year," he said. "It might be best to break it up if we can do large segments of it."

The freshman senator said he is particularly looking forward to the challenges of a new position as chairman of a key panel of the Foreign Relations Committee. The Near Eastern and South and Asian subcommittee has jurisdiction over U.S. ties to about 30 countries with seemingly limitless perils.

In his new role, Mr. Casey said he planned a major trip to the Middle East and Asia, likely in May.

Closer to home, Mr. Casey said he planned to work with Mr. Specter on setting up some form of structure to recommend names for three new U.S. attorneys to be appointed by the new administration. Mr. Casey added that he was amused and puzzled by published speculation on short lists of likely candidates for the coveted positions.

"Believe me," he said, "There are no lists written down anywhere. I don't even have a list in my head ... Some of this [handicapping of candidates] is literally pure fiction."

While their relative influence on Justice Department appointees has been fundamentally altered by the fact that the ultimate patronage decider is now a Democrat, Mr. Casey said he anticipated that he and Mr. Specter would act collegially on the appointments.

"He's the ranking [Republican] Judiciary Committee member and because of that he's entitled to play a significant role," Mr. Casey said.

Justice Ruth Bader Ginsburg's recent treatment for cancer was a reminder that Mr. Specter could again be in the spotlight should the committee have to consider a Supreme Court appointment during the next term. The Republican has already lobbied the White House to demonstrate bipartisanship on judicial selection by carrying on with the nominations of several unconfirmed judicial candidates originally nominated by former President George W. Bush.

Mr. Specter sent less bipartisan signals in the first days of the administration when he offered initial reservations about the fitness of Mr. Holder, the justice nominee. He ended up supporting him, however. The Republican's sometimes bipartisan stance was most prominently on display as one of only three GOP members -- in both chambers -- to vote for the president's stimulus package.

The joint power of appropriations and seniority is also the foundation of the acknowledged master of influence in the state's House delegation. Who's the most powerful state House member from Pennsylvania?

No knowledgeable observer has to think twice.

"Murtha, certainly, because of his seniority," said Rep. Tim Murphy, R-Upper St. Clair.

"Obviously, Jack Murtha is one of the cardinals," said Rep. Mike Doyle, D-Forest Hills. "He's the chair of that committee [the Defense subcommittee of the House Appropriations Committee]; he's the most senior, the dean of our delegation. It's pretty much hands down that he's the most influential."

In addition to his own power base, Mr. Murtha is close to Speaker Nancy Pelosi. He was rebuffed in the last Congress in an unsuccessful bid for majority leader, but he won re-election easily despite a well-funded opponent and some ill-chosen observations about the racist heritage of his district.

Perhaps the only potential threat to Mr. Murtha's continued clout are the controversies and simmering investigations over its source -- the projects and funding that he reliably returns, not only to his own district but to southwestern Pennsylvania and the state in general.

Mr. Murtha has not been charged with any wrongdoing, but federal prosecutors have been investigating a variety of firms that were the beneficiaries of the dollars that flow through his panel. If those investigations were to enmesh Mr. Murtha directly, Pennsylvania's congressional politics would be profoundly changed. So far, however, there has been no evidence that they will.

Another senior member of the group is Rep. Paul Kanjorski, D-Scranton, who will continue to be preoccupied with the stimulus/bailout/recovery debate as the second-ranking Democrat on the House Financial Services Committee.

Other Pennsylvanians with senior House posts include Rep. Chaka Fattah, D-Phila., the state's only other member, with Mr. Murtha, on the powerful appropriations committee. Another Philadelphian, Rep. Allyson Schwartz, won a spot last session as the state's only member of the similarly powerful Ways and Means Committee, which has jurisdiction on all tax issues.

Controversies to come

Some of the other most coveted House committee spots are on the Energy and Commerce panel, which has broad jurisdiction over issues including health care, and environmental issues.

Mr. Doyle is the state's senior Democrat on the panel. Heading its agenda are the hugely contentious issues of climate change legislation and health care reform.

Mr. Doyle argues that action on climate change is well overdue, but he said one of his chief priorities will be the effort to craft controls on carbon emission that do not hamstring heavy manufacturers, such as the steel industry.

"We have to level the playing field," Mr. Doyle said. "If we don't do that, all of these industries are going to move their factories to places like China and Brazil that don't have those rules, then we'd end up with fewer jobs and no gain for the environment."

In addition to the climate change hurdle, the committee also hopes to deal with health care reform, one of the centerpieces of the new administration's campaign promises

Mr. Doyle's neighbor, Mr. Murphy, is also a member of Energy and Commerce, but his influence is limited by his status as a member of the minority. Like his Democratic colleague, he said that one of his major concerns in the coming session is that any effort to cap carbon emissions does not penalize industries such as steel and coal.

Mr. Murphy came to Congress as a member of the majority. He said he found that minority status "requires a lot more political skills.''

"What I recognize is, as you come up with great ideas, ideas that have merit, you can go to members on the other side.''

He noted that he's worked with Rep. Patrick Kennedy, D-Rhode Island, as co-chair of a health care caucus that's championed efforts to improve health care technology, a goal that's also addressed in the stimulus legislation. In another example of reaching across party lines, Mr. Murphy joined Rep. Jason Altmire, D-McCandless, last summer in a pair of joint town meetings in their adjoining districts.

Mr. Altmire, entering his second term, is one of several Pennsylvania members of the Transportation Committee, which will be preoccupied by the effort to enact a new five-year template for highway and transit spending. The existing highway legislation is due to expire on Oct. 1. Its successor could authorize as much as $600 million in spending.

Mr. Altmire said members of the state's delegation, including fellow committee members such as Rep. Bill Shuster, R-Hollidaysburg, and Rep. Tim Holden, D-Pottsville, the senior Pennsylvania Democrat on the panel, were working together on the pending bill.

"We take a very regional approach; for me that's a priority," he said. "This is something that only happens every five years, so we don't want to miss that opportunity."

Representing the district immediately north of Mr. Altmire's suburban Pittsburgh seat is Rep. Dahlkemper, the newest Democrat in the state's congressional contingent. The Erie freshman sits on the committees on Agriculture, Small Business, and Science and Technology.

Ms. Dahlkemper said she was pleased by the Agriculture assignment because of the extensive rural areas in her district. Also, her spot on one of its subcommittees includes oversight on nutrition, an area in which she has particular expertise due to her background as a nutritionist and interest in prevention of childhood obesity.

"When we look at feeding people, our government needs to be the leader in terms of prevention," she said. "There are some really exciting things we can do to help those who are most needy to make healthier choices."

In a year in which health care reform should occupy a major part of the legislative agenda, Ms. Dahlkemper said she planned to weigh in on that debate through her position on a Small Business subcommittee that evaluates the impact of health care regulation on smaller firms.

But Mr. Doyle cautions that those issues, like the major rewrite of transportation legislation that's due this year, will be debated in the context of the economic crisis that has dominated the first weeks of the new Congress.

"The stimulus and the economy is going to dictate what we can do and how big we can think," he said.