The Pennsylvania 6th congressional district comprises parts of Chester, Montgomery, Berks and Lehigh Counties.
The incumbent, Republican Jim Gerlach, is one of the few Republicans who kept his seat during the Democratic congressional sweep two years ago.
His challenger, Democrat Bob Roggio, is a retired business executive.
Gerlach, many believe, is safe in the 6th district seat he has won narrowly three times now, despite President Bush's unpopularity.
He says he's primed to withstand the fallout from the top of his ticket or the White House.
"There's a good number of issues that I've separated myself from the President on from the farm bill to stem cell research," Gerlach said. "I opposed President Bush's social security privatization plan."
Retired small business owner Bob Roggio, from Malvern, is Gerlach's latest challenger. He puts the country's troubles squarely at the feet of President Bush and, by extension, Jim Gerlach.
"If you go to the key items that we really care about in the 6th district right now are the economy, health care, Iraq, and the environment," Roggio said. "He has been tied in very closesly to Bush on all four of those items."
For the first time ever in the 6th, registered Democrats outnumber Republicans.
The Obama campaign has been a registration dynamo in Pennsylvania and other key battleground states.
"I think Barack Obama is going to do very, very well in the 6th district, and I think he's going to have some pull with all Democrats and he's going to get out the vote that I, myself, might not have been able to get out," Roggio said.
Gerlach says he's happy with the McCain ticket, including his lightning rod running mate.
"She's as qualified as Sen. Obama, she has more executive experience," Gerlach said.
Gerlach has, by far, the larger campaign war chest, even in what is being called a Democratic year.
And the conventional wisdom is, it gets tougher to defeat an incumbent congressman for every 2 years he can hold on.