Republicans now hold a slim majority and Democrats need a net gain of eight seats to regain the control they lost in 1994. Although late mail-ins in California could also determine the outcome of up to a half-dozen races there, it's Washington's 1st and 2nd districts that are more likely to be the last in the country to determine a winner.

More than 50 percent of Washington's voters are expected to mail absentee ballots, which don't need to be postmarked until Election Day.

Two years ago, it took more than a week to count all the mail-in votes and determine which party would control the state's Legislature. This year, the stakes are much higher.

"These two seats could end up deciding who controls the House of Representatives," said Randy Pepple, a Seattle-based Republican political consultant. "They're both very close."

There is little that is automatic with independent Washington voters this year. The races for president, U.S. Senate and control of the state's House and Senate also are still too close to call.

"It most assuredly will put a lot of focus on a cold and northwestern-most part of the country," said Democratic political consultant Cathy Allen of Seattle. "They'll be carrying those absentee ballots in and we'll be watching every one of them."

In the 1st District, freshman Democrat Jay Inslee is defending his seat against a strong challenge by Republican state Sen. Dan McDonald.

In the 2nd District, Republican John Koster and Democrat Rick Larsen are fighting for the open seat left by Republican Jack Metcalf, who is abiding by his promise six years ago to serve only three terms.

The district covers the northwest corner of Washington, stretching from the northernmost suburbs of Seattle up to the Canadian border. A mix of suburbs and farmlands, it has traditionally been Democratic. Metcalf was the district's first GOP congressman in 30 years.

Both Larsen and Koster are relative unknowns. Larsen, the Democrat, raised more money than Koster and was favored until the state's open primary, when Koster won 49 percent of the vote to Larsen's 46 percent.

"A lot of Republicans were pleasantly surprised," Pepple said. "Democrats had been talking that race up as almost an automatic Democratic takeback."

"I see the 2nd District as a pure tossup," said Amy Walter, an editor for the nonpartisan Cook Report on politics in the nation's capital. "The candidate who adequately portrays himself as moderate, and is able to push his opponent off to the fringes, is the candidate who wins."

Political action committees have dumped hundreds of thousands of dollars into the race. Unions and abortion-rights groups support Larsen, while Koster has the gun lobby and anti-abortion groups.

Through the end of September, Larsen had collected $895,427, while Koster raised $623,769. The candidates' spending will easily be dwarfed by so-called "soft money" spent on TV ads and mailings.

While the 1st District race isn't as hot as the Koster-Larsen matchup, it remains crucial for both parties.

One-term incumbent Inslee did better than expected in the primary, winning 56 percent of the vote. But in a district that switched parties three times in the 1990s and hasn't re-elected a Democratic incumbent in 50 years, Inslee can't be too comfortable.

The swing district arches over Seattle, covering mostly suburban territory around all but southern parts of the city. Microsoft's main campus falls in Inslee's district, and he has carefully distanced himself from the Clinton administration's antitrust litigation.

"Democrats can't afford to lose either one of these seats," Walter said. "Washington state could be the linchpin for the Democratic majority. It could be literally down to one seat."