Pennsylvania State Rep. Curtis Thomas is a big man with a big voice. And when he took to the stage at the George Washington Carver community center in Norristown, Pennsylvania this weekend to exhort his fellow Democrats, his audience was primed and ready.

"We have to go out next Tuesday, kick butt and take names," he hollered. "We have to vote like we lost our minds!"

Democrats here are giddy. Three Republican seats are up for grabs in districts that stretch from leafy Main Line suburbs to gritty and depressed riverfront industrial towns.

Come Tuesday night, the Republican incumbents -- Curt Weldon, Mike Fitzpatrick and Jim Gerlach -- could be the first casualties of the public's generally bad mood this year. Each man has spent the better part of the past year dodging political bullets, establishing arms-length relationships with the White House, and struggling to explain their support for the Iraq War.

That has worked better for some than others. Weldon, a ten-term incumbent, appears to be in the most severe trouble. He drew a strong opponent -- an antiwar retired admiral, no less -- and he is under Federal investigation for allegedly conspiring to steer contracts to his daughter Karen.

Weldon is not taking it well. At a press conference called to tout his endorsement by a group of law enforcement officials, he unloaded on opponent Joe Sestak, who he derides as a carpetbagger who knows nothing about his district.

"My opponent has no clue," Weldon said. "If he were here, he wouldn't know one of the police chiefs behind me. And that's an indictment. But that's what politics is about this year. It's about the national mood. And it's about what money can do to come into a district and basically attempt to take that seat away."

And there has been a lot of money -- about $3 million spent on each campaign by national parties, and almost that much again raised by the candidates themselves. Weldon says he is spending more this time than he has in all 10 of his previous Congressional campaigns put together.

But the national party pulled the money plug on Weldon this weekend, as clear an indication as any of his fading reelection chances. The massive front-page headline in Saturday's Philadelphia Inquirer? "A Wounded Weldon Cuts TV Advertising."

That cash is going instead to Gerlach and Fitzpatrick, who have flooded the expensive Philadelphia television and radio airwaves with an onslaught of ads attacking what they say are their opponents' inexperience, dishonesty and liberal tendencies.

Fitzpatrick, a one-term Congressman, takes pains never to mention the word "Republican" in interviews or public appearances. When the camera stopped rolling, he freely admitted to me that he encouraged national party leaders to send Laura, not George, Bush to campaign for him. Sunday, he embraced Senator John McCain.

Fitzpatrick's supporters also do not mind drawing attention to Democratic opponent Patrick Murphy's babyfaced youthfulness. Murphy, an Iraq war veteran, is 33.

"I look at Michael, and I see a man who not only looks like a Congressman," Jim Matthews said at a sun-dappled rally Sunday in Washington Crossing. "But someone who is a great Congressman." Matthews is running for lieutenant governor with GOP nominee Lynn Swann -- but the two are so far behind that incumbent governor Rendell spends his days campaigning for others.

Murphy's response? He just talks about the "buddies" he lost in Iraq.

Bouncing back and forth between Democratic and Republican rallies this weekend, it was easy to spin anecdotal observation into grand conclusion. One event billed as a GOP rally turned out to be a cocktail party with an open bar. But at a Democratic rally featuring rock star-of-the-moment Barack Obama, lines snaked around the block for hours before the scheduled start time.

"We have good reason to be optimistic," Obama said. "But we don't have reason to be complacent."

The Democrats -- unified and ecstatic -- are in a sign-waving frenzy tempered only by the dread that it could all fall apart if voters stay home Tuesday (some rain is in the forecast).

The Republicans -- campaigning apart from each other -- generally draw smaller crowds peppered with dread of a different sort. Their majority might be slipping away. At the Fitzpatrick rally Sunday, a dozen men wearing tags printed with the word "security," systematically worked the crowd to eject anyone who could be identified as a Democrat. When someone driving by shouted something unintelligble from an open window, the tag-wearing men turned and glared down the road after the car, as if they might give chase on foot.

Contrast that to Rendell, gleefully holding hands at the Carver center with Nancy Pelosi, Barack Obama, Gerlach challenger Lois Murphy and a handful of dazed-looking state house candidates before a chanting, cheering crowd. No IDs were checked in that room.

"These will be 200-vote elections," Rendell said, warning of possible slim victories. "So don't anyone dare think of staying home. The only way we lose is if we let up."

One more sign that the Democrats are in a good mood? They're even willing to joke about the bad stuff.

"I was invited here today to make a few light remarks," State Rep. Daylin Leach said as he was playing for time at Cabrini College in Radnor, waiting for Sestak to arrive. "We figured Democrats were having such great luck making jokes this week, we'd keep the ball rolling."

Big laugh.

John Kerry, are you listening?

-- By Gwen Ifill for the Online NewsHour