Democrats hold solid leads for four of the six Republican seats they need to capture the Senate and about 10 of 15 required to win the House, according to officials in both parties. Numerous additional races remain highly competitive.

After two weeks of adverse publicity linked to the Mark Foley scandal, public and private polling suggested partial recovery for some endangered Republican incumbents, and senior party officials made a concerted effort to project confidence.

"By many measures, there are strong indications of a right-of-center base that is engaged and committed," party chairman Ken Mehlman said Friday in a memo written for public consumption.

The assertion was a response to independent polls that show disapproval of President Bush's policies, including on the Iraq war, and discontent with Congress have made Democrats more eager to vote on Nov. 7 than Republicans.

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At the same time, Democrats said unexpected opportunities for gains keep coming their way — including House races in Minnesota, Idaho and Nevada — and they have the money needed to battle Republicans to the end.

"We have enough to play defense in the blue states and offense in the red states," said Sen. Chuck Schumer of New York, who heads the Democratic senatorial committee.

After months of stockpiling their millions, candidates and the parties are spending freely in the final days before Election Day.

The National Republican Congressional Committee has spent more than $3 million to hold the seat of Ohio Rep. Bob Ney. Ney, who recently pleaded guilty to corruption charges, has yet to resign, but is not seeking a new term.

The GOP has invested more than $8 million into the Philadelphia suburbs and a northeast Pennsylvania district, where Republican Reps. Michael Fitzpatrick, Curt Weldon, Jim Gerlach and Don Sherwood face strong challenges. Democrats have put in nearly $7 million.

In Connecticut, GOP Reps. Chris Shays, Nancy Johnson and Rob Simmons face difficult challenges, although Republicans hope that Sen. Joseph Lieberman's independent candidacy will help them.

By contrast, Republicans have few opportunities to take away House or Senate seats belonging to Democrats. Georgia, where the GOP is aiming at two House seats, is one such case.

In the battle for the Senate, public and private polling shows Democratic challengers leading incumbents in Pennsylvania, Montana and Rhode Island as well as in Ohio, where the entire GOP ticket is struggling.

Officials who discussed the private surveys did so on condition of anonymity, saying they were not authorized to speak publicly.

Eager to offset likely losses, the National Republican Senatorial Committee has aired television commercials in New Jersey, hoping that Tom Kean Jr. can defeat Sen. Bob Menendez. Democrats countered quickly, with four times as much money.

Republicans apparently have not abandoned all hope in Michigan, either. President Bush is scheduled to campaign for challenger Mike Bouchard on Thursday. A party-financed television advertising campaign is possible, as well, aimed at toppling Democratic Sen. Debbie Stabenow.

Increasingly, though, officials in both parties said the battle for Senate control probably will come down to close races in Missouri, Tennessee and Virginia. All three are Republican-held seats where Democratic challengers have exceeded precampaign expectations.

Under most scenarios, Democrats would have to win two of the three to gain a majority.

In Tennessee, Republicans concede that Rep. Harold Ford has proved to be the most adept of the Democratic challengers this year. Democrats say Republican Bob Corker's campaign has been sharper and more effective since a staff shake-up this month.

Democrats in Missouri hope challenger Claire McCaskill will benefit from support for statewide initiatives on stem cell research and a higher minimum wage. She is running against Sen. Jim Talent.

The closeness of the Virginia race, where Jim Webb is taking on Sen. George Allen, is the biggest surprise of the campaign season. Like other Republicans, Allen has begun edging away from Bush's war policy. "The situation there is one that needs adjustments, that needs changes in tactics," he said Friday.

Many Republicans turned pessimistic about their party's chances of holding the House when the Foley scandal broke. The Florida congressman abruptly resigned on Sept. 29 after he was confronted with sexually explicit Internet messages he had written teenage male pages.

The House ethics committee is investigating, and Republicans are working to shift the campaign spotlight elsewhere.

"National security, border security, and the economy: these are the issues that matter most to the American people as we confront challenges domestically and abroad," House Majority Leader John Boehner, R-Ohio, advised fellow Republicans.

Despite Mehlman's efforts at reassurance, some candidates remain concerned. "The Republicans are a bit disillusioned," said Rep. Chris Chocola, struggling in his bid for a third term in Indiana.

The House Republicans in greatest danger of defeat include Reps. Charles Taylor of North Carolina and John Hostettler of Indiana, and Sherwood and Weldon of Pennsylvania, according to private polls. Of those incumbents, only Hostettler is not campaigning against a backdrop of scandal, either personal or political.

In addition, Democrats lead for open seats currently in Republican hands in Arizona, Colorado, Florida, Ohio and Texas.

The situation in Foley's former district is unpredictable. Foley's name is staying on the ballot and votes for him will be counted for replacement candidate Joe Negron.

Two members of the Republican leadership, Reps. Deborah Pryce of Ohio and Tom Reynolds of New York, have fought back from earlier deficits and made their races competitive, according to strategists.

Many other races remain competitive, judging from public polls and party spending.

Republicans in that category include Reps. Fitzpatrick, Gerlach and Melissa Hart in Pennsylvania; Clay Shaw in Florida; Mike Sodrel and Chocola in Indiana; Geoff Davis in Kentucky; Heather Wilson in New Mexico; Marilyn Musgrave in Colorado, Dave Reichert in Washington; Thelma Drake in Virginia; Steve Chabot in Ohio; and Gil Gutnecht in Minnesota.

Democrats also are mounting strong challenges for Republican-held open seats in Idaho, Illinois, Iowa, Minnesota and Wisconsin.

Relatively few Democratic-held seats appear in jeopardy.

Republicans have scaled back their initial target list, and continued to advertise against Reps. Jim Marshall and John Barrow in Georgia; Melissa Bean in Illinois; Leonard Boswell in Iowa; and in an open-seat race in Vermont.