WASHINGTON -- Democratic Congressman Chris Carney won election in Pennsylvania's 10th District in 2006 partly because of a wave of anti-GOP sentiment in the country, and partly because his opponent, Republican incumbent Don Sherwood, was accused of choking his mistress.

Carney, a former Naval Reserve officer who analyzed CIA intelligence at the Pentagon after Sept. 11, 2001, is now one of a group of Democratic freshmen representing Republican-dominated districts who must prove to their conservative constituents that they were the right choice to represent them two years ago. Theirs could be some of the most competitive House races of 2008.

Like other freshmen Democrats whose opponents' scandals helped them get to Washington, Carney has joined the House Blue Dog coalition, a 49-member group of Democrats who pursue moderate-to-conservative positions on both fiscal and social issues.

"The American people are looking for pragmatists rather than ideologically driven candidates," said Rep. John Tanner, D-Tenn., a long time Blue Dog, in a recent interview about the members "quietly raising their influence" on Capitol Hill.

Being a strong Democrat while sometimes opposing Democratic priorities won't force Carney into an ideological pretzel to keep his seat, insists campaign spokeswoman Rebecca Gale.

"Representative Carney always votes his conscience and puts the people of the 10th District ahead of the political party," she said.

But can some of the more vulnerable Democrats say the same?

Blue Dog Democrats are winning races on GOP turf because they are right on the issues at a time when Republicans are suffering from an identity problem, said Doug Thornell, spokesman for the Democratic Congressional Campaign Committee. He points to three recent special-election wins for Democrats in traditionally conservative districts in Louisiana, Mississippi and Illinois.

The political landscape favors the Democrats this year, according to most polls. With few viable targets, Republicans are concentrating on regaining seats in GOP territory that they lost two years ago.

The "pure toss-ups," according to political oddsmakers like the Rothenberg Political Report, include Carney as well as Rep. Tim Mahoney, D-Fla., who won his seat after Republican Rep. Mark Foley was caught engaging in lewd communications with House pages.

Other key races are in conservative districts held by Reps. Jerry McNerney, D-Calif.; Gabrielle Giffords, D-Ariz.; Nancy Boyda, D-Kan.; Nick Lampson, D-Texas; Baron Hill, D-Ind.; Zack Space, D-Ohio; and Kirsten Gillibrand, D-N.Y. McNerney, Space, Lampson and Gillibrand won seats held by Republicans tainted by scandal.

All of these freshmen save McNerney and Boyda are now Blue Dogs, and most have cast votes and taken positions that have set them apart from the liberals in the House.

Gillibrand, for instance, is a supporter of gun rights and co-sponsored a bill lifting the gun ban in the District of Columbia. Last month she sent out a mailing touting the fact that she was "the first member" of Congress to announce her opposition to former Gov. Eliot Spitzer's plan to give drivers' licenses to illegal immigrants in New York.

For his part, Carney has been the target of liberal activists who see him as a Republican in Democratic clothing. He has drawn fire for pushing to pass a new Federal Intelligence Surveillance Act (FISA) that would strengthen surveillance powers and give immunity to telecommunication companies that helped federal authorities engage in warrantless wiretapping.

Carney "sold out the Constitution for tens of thousands in campaign contributions from the big phone companies who broke the law by letting the government spy on you, read your e-mails and record your phone calls -- all without warrants. ... It's un-American," says an ad distributed by Blue America PAC, which is raising money through the online activist community to target Blue Dogs.

Can't Please Them All

Despite the assault from the left, Terry Madonna, director of the Keystone Poll at Pennsylvania's Franklin & Marshall College, said Carney and other Blue Dogs will face aggressive challenges from the right this fall.

"If anything, they're going to get attacked for being too liberal," Madonna said. "I think [Carney's] been a pretty remarkable centrist, Blue Dog'ish. I didn't see anything that stuck me as what I'd call dangerous politically in his votes so far."

Republicans and their supporters warn that not only are these Democrats vulnerable, they are not as independent from their parties as they claim. According to The Washington Post, these freshmen from conservative districts voted with the Democrats no less than 83 percent of the time.

Lampson, who took the seat held by House Majority Leader Tom DeLay, broke with his party the most, earning the 83 percent ratio. Hill voted with the party 87 percent of the time, Carney 88 percent, Mahoney 91 percent, Gillibrand 93 percent and McNerney 94 of the time, the newspaper reported.

"They have been too willing to toe the line for Nancy Pelosi on issues like taxes, spending and immigration," said Ken Spain, spokesman for the National Republican Congressional Campaign. "The case we're making to voters in these districts is their member of Congress says one thing at home and he's doing something very different in Washington."

This is the message that Carney's opponent, Republican Chris Hackett, would like to exploit. "You look at the broad spectrum of votes," he says, "and you see how Chris Carney has been on the liberal side of these votes."

Observers say the challenge in these closely divided districts is not to push either ideological extreme too far. Carney's district, according to the latest figures, is 48 percent Republican, 41 percent Democrat and the rest independent.

"They campaigned on a pledge to do what's best for their district and they've put together a record of independence that shows they've kept their pledge," said Thornell. "At the end of the day they are doing what they believe is best for their districts, and voters are going to reward them for that."

The Associated Press contributed to this report.