With voters in a decidedly anti-establishment mood, House Democrats have a lot to worry about. They're facing dozens of challenges across the country, especially in moderate districts and swing states.
Some of the most vulnerable Democrats are the ones that gave Speaker Nancy Pelosi her majority in the first place.
In January 2007, the triumphant new speaker of the House gazed into a crowd of new faces: "Looking around this room, it's clear that Democrats are back," she said.
Pelosi called them the Majority Makers -- a new crop of Democrats from moderate to conservative districts that pushed her party over the top in the House.
Two years later, a vibrant presidential candidate and a strong message of change helped boost House Democrats' ranks, and their triumph seemed solid.
But now political ads are taking on Democratic freshmen and sophomores with messages like:
"Just how fast is Congressman Zack Space spending your money?"
"Democrats like Betsy Markey voted for a corrupt bill."
"Is Gabrielle Giffords' political career on life support?"
"Bobby Bright. He's supporting Obamacare now. He's just hoping we won't notice."
Republicans would like to make those Majority Makers the Majority Takers, precisely because they represent swing districts.
"I think the voter across America has learned a whole lot more about the changes Barack Obama and Nancy Pelosi had in mind for the country," says Rep. Pete Sessions (R-TX), who's in charge of getting those seats back for his party.
He says Democratic leaders pushed the moderates too far when they brought cap and trade energy legislation and the health care bill to the floor. And, Sessions says, voters have watched the economy bottom out and the deficits explode.
"It is causing all across this country, in Republican and Democrat primaries, a debate about the role of government, about the significance of our debt problem, and the unemployment that has not turned around," he says.
Come November, he says, moderate voters will turn back to the Republicans.
To which centrist Democrats say: not so fast.
"I just think that leadership is about action, not position," says freshman Rep. John Boccieri (D-OH).
"We campaigned for office understanding that we've got to make, not only promises when we campaign, but when you govern it's about choices," Boccieri says.
Sure, Boccieri says, there were hard votes: on health care, the economic stimulus and Wall Street regulations. But he's telling voters that all of those things would have gotten worse if Republicans had been in charge.
"Part of this new generation of politics is about not looking at politics as a career but as a place to solve problems," says freshman Rep. Tom Perriello (D-VA).
The Republicans are making a miscalculation, he says, if they think they can convince voters that these moderates are just party-line Democrats -- adding that's not why he got in to the job.
"I thought neither party had the guts to take on the big issues of our day -- things like energy independence, health care reform and deficit reduction," Perriello says, "and that's what I'm here to do. I'm gonna keep swinging to the fences on solving America's problems with bold but pragmatic solutions, and I think that's what people back home are looking for."
This week Democrats saw a glimmer of hope that their focus might be working, says the man in charge of safeguarding their majority, Maryland's Chris Van Hollen.
"The one race in the country on Tuesday where you had a matchup with a Democrat and a Republican was the Pennsylvania 12 special election," Van Hollen says.
That's the longtime Democratically held seat that the GOP hoped to take as a trophy.
"The Republican strategy of trying to scare people by saying ooooooh Nancy Pelosi and Barack Obama and send them a message -- it fell flat," Van Hollen adds.
Democrat Mark Critz won the seat held by the late John Murtha, at least for the rest of this term. In November, there will be a rematch -- and a much bigger test of moderate Democrats' staying power.