Rep. Don Sherwood, conservative Republican and bringer of bacon to his home district in northeastern Pennsylvania, is used to adversity.

In his first election campaign in 1998, he beat his Democratic challenger, Pat Casey, by a mere 515 votes. Even though redistricting has made his constituency more Republican, and he hasn't had a serious challenge since the Casey rematch in 2000, Sherwood has suddenly landed on the list of vulnerable GOP incumbents, an increasingly familiar distinction ahead of the fall midterm election.

"What put this race in play was the closeness of the primary," said Terry Madonna, public affairs professor at Franklin and Marshall College in Pennsylvania.

"Is it a problem the Republican Party is generally going to have this year, or is it more personal" for Sherwood? It's probably a combination of both," Madonna said.

In the May 16 GOP primary, Sherwood beat back Kathy Scott, a virtually unknown Republican, 56 to 44 percent. The fact that a candidate with no name recognition and little funding was able to get so close was a wake-up call for the 65-year-old incumbent, a Tunkhannock resident.

But Sherwood's problems don't all stem from the anti-Republican malaise that has been expressed in national polls and is dogging candidates in competitive districts everywhere. Late last year, he agreed to a confidential settlement in a $5.5 million lawsuit filed by a 30-year-old woman who claimed the two had carried on an affair for five years and that Sherwood physically abused her.

"The behavior was inappropriate," said Maurine Giordano, former chairwoman of the Pike County Democratic Party, who predicted Sherwood's lackluster showing in the primary. "Most of us are pretty disappointed with our representation here."

Sherwood acknowledges that his extramarital affair played a role in the primary, telling reporters afterward that he "got that message."

"Obviously, it had some effect on the primary, but people know me pretty well and they know how hard I work," Sherwood said in an interview. "I've apologized to my family, and the voters, but now I think we need to get beyond that and work at the things that are important to the 10th District."

An auto dealer and former school board member, Sherwood faces what Democrats are saying is one of their best recruits yet: Chris Carney, a 46-year-old Naval Reserve officer who served as a consultant on counterterrorism issues for the Pentagon after the Sept. 11, 2001, terror attacks.

"Voters are looking for a change from the current corrupt leadership in Washington," said Jen Psaki, spokeswoman for the Democratic Congressional Campaign Committee. "Carney's background as an educator and member of the Naval Reserves could not offer more of a contrast."

Carney, a native of Iowa, moved to Pennsylvania in 1992 for an assistant professorship at Pennsylvania State University, where he still teaches U.S. foreign policy, U.S. security policy and American government.

"Don Sherwood really hasn't represented our values or our interests in Washington," Carney told FOXNews.com. "People are ready for a change."

Democrats say they have internal polling suggesting a statistical dead heat between the two men, but no independent polls of the race have been taken so far. Republicans, however, suggest Democrats might be exaggerating Sherwood's vulnerabilities.

"The Democrats have been pushing that for several weeks as they have been pushing similar lines in similar districts," said Ed Patru, spokesman for the National Republican Congressional Committee. "It's all part of an effort to manufacture momentum and expand the playing field. Democrats are living in a fantasy world in respect to the 10th District."

As the strategies of the two campaigns unfold, it is clear that Sherwood is trying to make the case that despite his personal failings, he has been a tireless advocate for his district, which includes the heavily rural, socially and fiscally conservative northeastern corner of the state. It spans Wayne, Union and Snyder Counties, and also includes Pike County, the fastest growing area of the state, which has drawn more and more New Yorkers and New Jersey families over the last several years.

Sherwood said as a member of the House Appropriations Committee for the last six years, he's helped dairy farmers, cut taxes and brought home money for roads and bridges in his district.

"I think one of the things that's brought out the people to vote for me is they realize I understand the district, what it needs economically and I'm still working on those issues," he said.

Fellow Pennsylvania Republican Rep. John Peterson, chairman of the House Rural Caucus, agrees. "He's made a name for himself down here as a vigorous defender of America's dairy farmers, but I'd say his work on energy, rural health care, and forestry issues has been equally impressive," Peterson said.

But Democrats say that Sherwood, who has styled himself a defender of family values in the past, has betrayed his constituents. He has also been a big supporter of President Bush, who won big in the district in the 2004 election.

Still, the president's waning popularity all over the country has seen no exception in Pennsylvania's 10th Congressional District, say people there. Abe Amoros, spokesman for the Democratic Party of Pennsylvania, says Carney is the antidote to a beleaguered community.

"The northeast is very blue collar, hard working, humble ... Chris Carney seems to be a very good candidate in terms of projecting those family values and very bright to boot," he said.

"That is a contrast with (Sherwood's) shenanigans and his support for the president," Amoros added. "This is a golden opportunity."

Carney argues that American soldiers were not sent into Iraq well equipped and he wants one U.S. battalion to return home from Iraq for every Iraqi battalion that the Pentagon says is adequately trained. He said Sherwood never asked "the tough questions" of the Bush administration and is now paying for it in declining support back home.

"We are fairly confident we will have a significant percentage of Republicans crossing over to us," he said.

Frank Golden, chairman of the Wayne County Republican Party, said Carney shouldn't count on that. Voters in the district see Sherwood as accessible and hardworking, he said.

"He's got time for the people," Golden said. "He's extremely responsive, probably the best I've seen."

Golden said conservative voters have little in common with the Democratic leadership in Washington, and will think twice on that score alone before voting for Carney. "I think in the primary, there were some votes [Sherwood] didn't get for reasons we all know," said Golden. "But I think anybody who might have stayed away in the primary will be 100 percent on board in the general election."