Reps. Peter King and Vito Fossella, once thought two of the most secure Republicans in the House, are emptying their war chests of hundreds of thousands of dollars to stem the tide of Democratic candidates riding the coattails of Senator Clinton and gubernatorial candidate Eliot Spitzer, who are expected to win by a landslide.

Mr. Fossella, the lone Republican in New York City’s congressional delegation, cruised to re-election in the 13th Congressional District in 2004, snaring 59% of the vote. This time, however, he is under greater pressure to distance himself from President Bush, who, though not on the ballot, suffers from low approval ratings in New York State.

And although his opponent, Stephen Harrison, has raised about $109,000 compared to Mr. Fossella’s $1.3 million and has not received financial support from the Democratic Congressional Campaign Committee, an expected strong Democratic turnout has obliged Mr. Fossella to go on the offensive.

In one television advertisement, Mr. Fossella, whose district includes Staten Island and part of Brooklyn, goes out of his way to declare his independence from the White House, noting his stand against the president’s plans to privatize Social Security and cut Medicare.

The congressman does follow the president’s lead on national security, however. “Harrison puts the rights of terrorists above the safety of you and your family,” a Fossella TV ad says. A recent Fossella campaign flier also included a photo of Mr. Harrison next to one of Osama bin Laden.

A spokesman for Mr. Fossella’s campaign, Craig Donner, defended the flier, saying Mr. bin Laden is the face of the terrorist threat and that Mr. Harrison has voiced opposition to the National Security Agency’s warrantless wiretapping program.

With corruption and scandal prominent issues this election season, Mr. Fossella recently found himself facing ethics questions of his own over reports, first published in the New York Daily News, that he used campaign funds to finance family ski trips to Vail, Colo. When asked about Mr. Fossella’s expenditures, Mr. Donner said, “Everything done by the campaign has been consistent with the law.”

In the 3rd Congressional District on Long Island, Mr. King, the chairman of the Committee on Homeland Security, is facing a well-financed Democratic candidate, David Mejias, a first-generation Cuban-American and Nassau County legislator.

While the two candidates disagree over the accuracy of a recent poll that shows them in a dead heat, the race is close enough to encourage Democratic supporters to reach into their pocketbooks. Mr. Mejias has raised more than $650,000, with roughly 75% coming from individuals.

The DCCC has taken note, adding Mr. Mejias to its Red to Blue program, which introduces congressional candidates to Democratic donors across the country.

A Democratic political consultant, Hank Sheinkopf, said both the Republican and Democratic parties view congressional races as investments. They will throw their support behind a candidate when polling numbers look favorable and when a particular candidate has shown an ability to raise money, he said.

Mr. Mejias said the support of the DCCC has opened up new fund-raising sources for the home stretch. (A spokeswoman for the DCCC would not comment on why Mr. Harrison’s race was not added to the online fund-raising push.)

Mr. King, meanwhile, has raised more than twice as much money as he did in 2004 — nearly $1.4 million — and has engaged in a vigorous campaign to highlight his accomplishments, including his stand against Mr. Bush over the Dubai Ports World deal earlier this year and his role in helping protect New York.

“King is trying to educate voters and emphasize his conservative stances,” a professor of political science at Hunter College, Ken Sherrill, said. He added that voters often know less about a Congress member’s achievements than what their political party has, or has not, done.

This has led Mr. Mejias to make frequent mention of political contributions Mr. King has received from Homeland Security interests and his consistent support for the war in Iraq.

On the campaign trail, Mr. Mejias has often repeated what Mr. King wrote to a constituent who in 2005 asked him to censure Mr. Bush: “I thank God every night that he [Bush] is our president.”

The King campaign did not respond to repeated requests for comment on the race.