Oct. 18 (Bloomberg) -- After Democrat Joe Sestak captured a suburban Philadelphia House seat from a Republican who had held it for two decades, he never stopped trolling for donations. Now, with a $1.4 million bankroll, he's considered a good bet to retain the seat in 2008.

Sestak, 55, is one of several freshman Democrats who have boosted their chances of hanging onto hard-won seats by using their fundraising prowess to scare off challengers. Others include Michael Arcuri in New York, Paul Hodes in New Hampshire and Dave Loebsack in Iowa.

Republicans' only chance for recapturing the House in 2008 hinges on defeating many of the 30 Democratic freshmen who won Republican-held seats in 2006. Prospects for that are fading as the party struggles to recruit challengers or to match Democrats' strong fundraising.

``There's no denying Democrats have the momentum,'' said former Republican Representative Jack Quinn of New York. ``To the victors go the spoils. That includes the fundraising. It's going to be another difficult year for Republicans.''

At the moment, Republicans aren't conceding any House races. ``Expect a surge of Republican candidates in the coming weeks,'' said Ken Spain, spokesman for the National Republican Congressional Committee.

First-term Democrats are raising funds early and often; 15 of them, including Sestak, were among the 50 incumbents taking in the most money through June 30.

`Don't Slow Down'

``We said, `Make sure you're in a position to get your message out. Don't slow down''' raising money, said Maryland Representative Chris Van Hollen, chairman of the Democratic Congressional Campaign Committee.

Sestak got the message. He makes about 60 fundraising calls a week, backed up by his brother and one of his six sisters. ``Politics is war by other means,'' said Sestak, a former Navy vice admiral, as he headed for a meet-and-greet event at the American Helicopter Museum's annual air show in West Chester and a tour of the Darlington Arts Center in Concord. ``You have to plan. You have to have your resources.''

The battle plan also includes spending every available moment meeting voters. The day after ousting 10-term incumbent Republican Curt Weldon, the subject of an FBI investigation, Sestak was out shaking commuters' hands at a train station. A believer in the perpetual campaign, he visits flea markets, holds town meetings, and marches in parades.

Early Money

Like Sestak, other freshmen Democrats favored to hold onto their seats are fattening campaign bank accounts more than a year before they next face the voters.

Hodes raised $834,711 through Sept. 30 with 13 months to go before the election. He didn't pull in that amount in his successful race last year against six-term Republican incumbent Charles Bass until two months were left in the campaign.

``Especially in New Hampshire, where traditionally congressional incumbents have not actively built their war chests, it shows that I'm serious about keeping this seat,'' Hodes said.

In New York, Arcuri, who toppled 12-term Republican Sherwood Boehlert, has raised $656,298, a funding level he didn't reach last year until three months before Election Day.

And in Iowa, Loebsack, who ousted 15-term incumbent Republican Jim Leach, has already raised $444,297, almost as much as his entire 2006 campaign.

Favored to Win

All four Democrats are favored to win by Congressional Quarterly, the Cook Political Report and the Rothenberg Political Report, Washington-based publications that handicap congressional races. None has drawn a serious opponent yet.

Sestak said his early fundraising could dissuade a challenger. ``If somebody's wavering, I want them to know it's going to be a tough campaign,'' he said.

Another deterrent may be Republicans' pessimism about their chances in 2008 under the weight of an unpopular presidency. A Sept. 27-30 Washington Post/ABC News poll put George W. Bush's approval rating at 33 percent.

``Bush drove me from the Republican Party, absolutely, because of the Iraq war,'' said Sandy Stevenson, a Sestak constituent from Garnett Valley.

In their quest to stay in the majority, Democrats also want to upend vulnerable House Republican incumbents such as Mark Kirk in Illinois and John Doolittle in California.

Abramoff Ties

An example is Charlie Brown, a Democrat who narrowly lost to Doolittle last year, who is running again and has raised $510,517 through Sept. 30 versus $355,581 for the incumbent.

The Justice Department is probing Doolittle's ties to former Republican lobbyist Jack Abramoff, who pleaded guilty in January 2006 to fraud, tax evasion and conspiracy to corrupt public officials.

In Illinois, two Democrats, Jay Footlik and Daniel Seals, both raised more than $480,000 as they vie to challenge Kirk, who has taken in $1.8 million.

Democrats ``make hard, cold calculations,'' Kirk, 48, said. ``If they see a well-funded incumbent who's working hard, the odds are in the nineties that they will not prevail.''

To contact the reporter on this story: Jonathan D. Salant in Media, Pennsylvania, at jsalant@bloomberg.net.

Last Updated: October 18, 2007 00:07 EDT