Two Republican officials with knowledge of the decision said Peterson was expected to announce his retirement. The officials spoke on condition of anonymity because they did not want to pre-empt the congressman's announcement, which was anticipated later Thursday.
No indication yet why he's leaving exactly, but he'll turn 70 this year.
Peterson was re-elected in 2006 with 60% of the vote, underpolling Bush by less than 1%. This is rough, red country to be certain (R+10), but it does include State College.
2006 challenger Don Hilliard says in a comment on Race Tracker Wiki:
Please note my name is Don Hilliard. I ran against Congressman Peterson in 2006 and intend to do so again in 2008. Please add me to your site. Thank you.
UPDATE: Wikipedia on Peterson's environmental record:
Peterson received the lowest possible environmental rating from the nonpartisan League of Conservation Voters in 2006, casting what the group qualified as anti-environment votes on twelve out of twelve critical issues ranging from oil drilling offshore and in the Arctic National Wildlife Refuge, salvage logging and logging roads, and the Clean Water Act, to the Toxics Release Inventory program and low-income energy assistance. The conservative environmental group Republicans for Environmental Protection singled out Peterson as "Worst in the House in 2006" on environmental issues. In addition to assigning the representative a score of zero for his voting record, REP censured him individually for "efforts to remove the moratorium on Outer Continental Shelf gas drilling through the Interior appropriations process." According to the League of Conservation Voters, "natural gas drilling can create massive amounts of water and air pollution and can leave open the possibility of oil spills, which would be toxic for a wide variety of marine and coastal life."
Peterson said in a statement released by his office that he desires to spend more time with his family in Pleasantville. He said his retirement is effective at the end of his current term.
Wow, it's like Republicans all over congress are suddenly remembering how much they love their families! I guess being on the Appropriations committee isn't as fun when you're in the minority.