PEABODY – U.S. Rep. John F. Tierney is giving serious thought to running for the congressional seat left vacant by the death of Sen. Edward M. Kennedy.Tierney, a Salem Democrat who represents the Sixth Congressional District in Massachusetts – en-compassing 36 communities including many along the North Shore – candidly discussed his musings Tuesday, emphasizing that no final decision has been made.The 57-year-old ranking member of the House of Representatives previously declined interview requests related to his political aspirations while Kennedy was undergoing treatment for a brain tumor.Kennedy, known as The Lion of the Senate, died Aug. 25. He was 77 and had served in the Senate for more than four decades.”In all honestly, we put this aside when the senator was sick and it certainly wasn’t an appropriate subject during his funeral,” said Tierney, a lawyer with blue-collar roots who was elected to the House in 1996 and began serving in 1997. “Since then, a lot of regular supporters have come forward with inquiries and encouragement. We owe it to these people to give it serious consideration.”But the ultimate decision won’t be easy because filling a Senate seat would impact Tierney’s personal and professional life.”We’ve been talking it over,” said Tierney, referring to his wife, Patrice. “There’s a lot to think about. This would be a big change in my life and in hers, for sure.”According to Tierney, among the more important factors is whether he would be able to continue at the Senate level his current work on health care reform, workforce investment, education and green technology.”My concern is that congressmen do a lot of work and I want to be part of it. I don’t want to miss out on opportunities to work on health care, the Green Jobs Act and on the Workforce Investment Act. Right now, I’m able to use my seniority to do that,” he said. “So the question will be, where is that work best done?”Tierney sits on four committees, the House Democratic Steering and Policy Committee, the House Select Committee on Intelligence, the House Committee on Education and Labor and the House Committee on Oversight and Government Reform. In addition, he is chairman of the House Oversight and Government Reform’s Subcommittee on National Security and Foreign Affairs. These posts have given him access to high-level government intelligence matters and prompted diplomatic visits to such places as Israel, Pakistan, Afghanistan and Turkey.The loss of membership on those key committees would be a drawback to pursuing a Senate seat, though new opportunities would surely arise as appointments are made to Senate committees.”I enjoy working in the House and have relationships there. We have shown an ability to get things done,” he said. “The people of Massachusetts want a senator who reflects a passion for things that affect our daily lives – health care, education, jobs. Things that make life better. Sen. Kennedy had a passion for those things and I share them.”The logistics of running for a Senate seat are complex. Candidates must organize supporters, raise funds, gather signatures, and coordinate a statewide name recognition campaign.The John Tierney for Congress Committee currently has $1.3 million in its account, putting Tierney on par with other legislators who also might be considering a run for the office.Tierney must also gather 10,000 signatures, the number required to get his name on the ballot. Since it would be a special election, the signatures must be submitted by Oct. 20.Under a 2004 state law, a special election must be held 145 to 160 days after a Senate seat becomes vacant, and the winner would serve out the remainder of the unexpired term. However, shortly before his death, Kennedy delivered a letter to Gov. Deval Patrick, requesting that the Legislature pass an amendment allowing the soon-to-be-vacant Senate seat to be filled by a temporary gubernatorial appointment who must also agree not to run in the special election.A hearing o