WASHINGTON - The Western Democrat is apparently no longer an endangered species.

Democrats in the Mountain West rode a national Democratic wave Tuesday to key victories in Montana, Colorado and Arizona, picking up seats in states long thought to be solidly Republican.

The wins reinforce what Western Democrats have said for years - that the region is a new frontier for the party, which has had to scrounge for electoral votes in the last two presidential contests.

The victories also left Democratic leaders in the region positive that the national party would hold its 2008 convention in Denver instead of New York. Party leaders will decide a location soon.

"The West is now the beacon for the Democratic Party," said Democratic New Mexico Gov. Bill Richardson. The election gains show "the West is the most fertile area to bring Democratic gains in 2008."

As of Wednesday, Democrats hold the governor's mansions in five of the eight mountain states, a majority of House seats in Colorado and half the House seats in Arizona.

Perhaps the biggest win was in Montana, where Democrat Jon Tester defeated three-term Republican Sen. Conrad Burns in contest that was so tight Burns had not conceded as of Wednesday afternoon.

Tester's win comes two years after Montanans elected popular Democratic Gov. Brian Schweitzer, a rancher and farmer. Tester will join fellow Montana Democrat, Sen. Max Baucus, in Washington. Next year, conservative Montana will have a bigger Democratic presence in its top jobs than Sen. Ted Kennedy's Massachusetts does right now.

"This is a huge change," said Rep. Diana DeGette, D-Colo.

Nationally, Democrats won a majority of seats in the House. Control of the Senate hinged on a down-to-the-wire Virginia race.

Democrats defeated a number of powerful Republicans, including House Resources Committee Chairman Rep. Richard Pombo, R-Calif. Pombo's proposals to sell public land and loosen endangered species rules may have helped turn some voters in the Mountain West against the GOP.

But DeGette said Western voters were motivated by the same things that caused voters across the country to oust Republicans.

"The voters of America and the voters of the West have realized the Republican Party is no longer the party of fiscal responsibility … and also that the Republicans have a failed policy in Iraq," she said.

The question now is whether Democrats will be able to hold onto their new seats in the West. Not for long, some Republicans said Wednesday.

"Last night's election was not a revolution, nor was it an endorsement of a true or real Democrat alternative," said Arizona Republican Rep. John Shadegg. "It was a rebuke of the way Washington has conducted itself as of late."

The Democrats' victories in the West build on 2004 victories for Schweitzer in Montana and brothers Sen. Ken Salazar and Rep. John Salazar in Colorado. The wins were bright spots in an otherwise dismal year for Democrats.

Independent political consultant Eric Sondermann of Denver said Western states have become more attractive for Democrats looking to pick up victories in national races. Part of the reason, Sondermann said, is what he sees as a backlash in the GOP to the socially conservative and religious strains of the party.

"That seems to a more fitting value system in the South than necessarily the frontier-based, anti-government, libertarian" values of the West, Sondermann said.

Schweitzer and the Salazars emphasize their support for farmers and veterans and the environment but stay away from the more divisive social issues. This year's Democratic winners, especially in Montana and Arizona, seem to fit the same mold.

Gabrielle Giffords, who will represent Arizona's 8th Congressional District, and Harry Mitchell, who defeated incumbent Rep. J.D. Hayworth in Arizona's 5th District, emphasized during the campaign that they supported President Bush and Arizona Republican Sen. John McCain's plan to enforce the border.

In Arizona, retiring GOP Rep. Jim Kolbe said he hopes the Republican losses "cause a serious reexamination of our party's roots and directions."

Kolbe, who has held his seat for 22 years, will be succeeded by Giffords.

"If Republicans are to provide leadership for our country, we must get back to the fundamentals of our party - an emphasis on national security, fiscal discipline, reducing government's role in our daily lives, embracing immigrants from other parts of the world, and a commitment to economic growth through lower taxes and increased trade," he said.