The dispiriting drip-drip-drip of retirements continued last week for House Republicans.

On two successive days, a leading moderate and a reliable Christian conservative — both still too young to be eligible for Social Security benefits — announced their plans to leave Congress at the end of the year.

The seat of 10-term Rep. Jim Walsh (N.Y.) already was in danger of flipping and now becomes even more endangered. And Democrats say they now at least have an outside shot of winning the seat being vacated by seven-term Rep. Dave Weldon (Fla.).

“These are two major blows to national Republicans already struggling with a disenchanted base, nonexistent message and a legacy of corruption and coziness to George Bush,” said Doug Thornell, a spokesman for the Democratic Congressional Campaign Committee. “We feel very good about our chances in New York 25 and are very optimistic that the right candidate puts Florida 15 in play. As he focuses his time and energy on getting a seat on the Appropriations Committee, this is yet another distraction for [National Republican Congressional Committee Chairman] Tom Cole [Okla.].”

While neither announcement was altogether surprising, both were shocking anyway, especially for a House Republican Conference that now has seen 21 Members head for the exits this cycle — not including those who are running for other offices or have died during the 110th Congress.

Both Weldon and Walsh are veteran members of the Appropriations Committee, and their departures mean six Republican appropriators are leaving this year.

Just hours after word of Weldon’s retirement started circulating Friday, a credible Democratic candidate, former Brevard County Commissioner Nancy Higgs, announced that she intends to run for his seat.

“This is really to me an extraordinary time in the country’s history,” Higgs told the newspaper Florida Today. “I think it is time to step up and bring change to Washington. And that’s what I intend to do.”

Up until Friday, only family doctor Steve Blythe was running for the Democratic nomination. Blythe had just $2,245 in cash on hand as of Sept. 30, the most recent filing date.

Republicans will still be favored to hold the east-central Florida 15th district. It gave President Bush 57 percent of the vote in the 2004 and 54 percent in 2000. Weldon had close calls in his first two races but has won fairly comfortably since.

“I am confident that the voters in Florida will send another hard-working Republican to Congress in 2008,” Cole said in a statement. “The NRCC will be committed to recruiting a Republican candidate who will continue to represent Florida’s 15th Congressional District with the same enthusiasm that Dave has.”

A Republican source familiar with Florida predicted Weldon’s retirement likely will set up a Republican primary showdown between conservative state Sens. Bill Posey and Mike Haridopolos. State Rep. Thad Altman (R) told Florida Today that he is “very interested” in running for the seat.

The filing deadline in Florida is May 2 — just around the time this year’s state legislative session is scheduled to end.

In central New York, meanwhile, Walsh’s retirement is undoubtedly good news for the Democrats, but it may not be the best news for former Congressional aide Dan Maffei (D), who came close to beating Walsh in 2006 and has been gearing up for a rematch ever since. Sometimes success (or near-success) breeds success, and other times it brings unwanted company — which is what Maffei may soon discover.

Since Walsh’s retirement announcement on Thursday, several other Democrats have been mentioned as possible candidates for the seat, including Syracuse Mayor Matt Driscoll, former professional football player Tim Green — a TV and radio commentator who has openly flirted with running for office before — state Sen. Dave Valesky and Syracuse City Councilwoman Stephanie Minor, who is personally wealthy.

Driscoll, a friend of Maffei’s — Maffei served as the campaign manager for his 2005 re-election — has told associates in recent days that he is considering joining the race.

Onondaga Democratic Party Chairwoman Diane Dwire on Friday told The (Syracuse) Post-Standard that the Walsh vacancy “is an incredible opportunity for the Democrats” and that a primary could be healthy for the party.

But DCCC leaders moved swiftly to shore up Maffei on Friday, making him the 11th candidate in their “Red to Blue” program, which gives financial and institutional support to candidates who have a chance of winning Republican seats.

“Dan Maffei is widely supported in Central New York, has a strong organization, and a compelling message of change for middle class families,” DCCC Chairman Chris Van Hollen (Md.) said in a statement. “The Red to Blue Program will give Dan the financial and structural edge to be even more competitive this year.”

Fueling Democrats’ optimism in New York is the fact that Maffei, who worked for the House Ways and Means Committee and then-Sens. Bill Bradley (D-N.J.) and Daniel Patrick Moynihan (D-N.Y.), gave Walsh the toughest race of his Congressional career, finishing just 3,400 votes behind the incumbent. The 25th district is one of just eight in the country that voted for Sen. John Kerry (D-Mass.) in 2004 but still is represented by a Republican on Capitol Hill.

Sources said that senior Democratic members of the New York delegation, led by House Ways and Means Chairman Charlie Rangel, worked behind the scenes to secure early DCCC help for Maffei. The powerful Service Employees International Union also is a key supporter of Maffei’s; one of his top strategists, Jennifer Cunningham, is a former longtime official in SEIU’s New York office who continues to be a consultant to the union.

But one Washington, D.C.-based Democratic operative who has talked to several of the players in the 25th district since Walsh’s retirement announcement said that with the Congressman out of the race, Maffei will have to change his strategy quickly to keep other Democrats from getting in.

“Dan has to produce a poll showing he can beat the other Republicans in the race,” the operative said. “He’s been focused on one thing — Walsh and Bush.”

Several Republicans are expected to take a look at the race, though it is unclear at this early stage who would be the most formidable. Potential candidates include Housing and Urban Development Deputy Secretary Roy Bernardi, a former Syracuse mayor; Monroe County Executive Maggie Brooks; former New York State Fair Director Peter Cappuccilli Jr.; Onondaga County District Attorney Bill Fitzpatrick; former state Sen. Nancy Larraine Hoffman; and former Onondaga County Legislature Chairman Dale Sweetland.

A moderate in Walsh’s mold might have a better chance in November than a doctrinaire conservative.

Cole, in a statement, was slightly less bullish on the GOP’s prospects in New York than he was for the party’s chances in Weldon’s district.

“I believe the voters of New York will send another hard-working Republican to Congress in 2008,” he said.

As for Walsh, 60, and Weldon, 54, both appear done with politics for now. Weldon, a physician whose 21-year-old daughter was arrested just hours before his retirement announcement for allegedly hitting a tavern bouncer, plans to return to his medical practice. Walsh, the senior Republican in the Empire State delegation, told reporters in Syracuse that he plans to look for a job either there or in Washington.

Matthew Murray and Lauren W. Whittington contributed to this report.