National Democratic gains reverberated in the Mountain States, with the loudest echo in Colorado, where Democrats claimed a decisive majority of the state’s Congressional delegation.

The Centennial State’s nine-member delegation will be dominated by seven Democrats in the next Congress, reducing the number of Republican-held seats by half.

Voters ejected incumbent GOP Rep. Marilyn Musgrave in favor of Democratic challenger and former Senate aide Betsy Markey.

Markey, who worked for Sen. Ken Salazar (D), becomes the first Democrat to represent the 4th district since 1972.

Musgrave, who gained notoriety for pushing a bill in 2004 to ban same-sex marriage, failed to duplicate the win that she eked out last cycle, despite the Republican lean of the eastern Colorado district.

In addition, Rep. Mark Udall (D) will ascend to the state’s open Senate seat, defeating ex-Rep. Bob Schaffer (R) to replace retiring Sen. Wayne Allard (R).

Former state Board of Education President Jared Polis (D) will fill the 2nd district seat now held by Udall, after defeating Republican Scott Starin in the heavily Democratic district.

The state’s open 6th district seat, vacated by retiring Rep. Tom Tancredo (R), will be filled by Colorado Secretary of State Mike Coffman (R), who overwhelmed Democrat Hank Eng in the solidly Republican district.

Idaho voters appear to have ousted freshman GOP Rep. Bill Sali from the 1st district in favor of Democrat Walk Minnick.

With 99 percent of the state’s vote tallied, Minnick, a wealthy former chief executive officer of a forest products company, leads 51 percent to 49 percent.

Minnick positioned himself in the race as a libertarian-style moderate and gained the backing of several high-profile Republicans, while Sali failed to win the support of the state’s top Republicans, including Gov. Butch Otter.

Republicans retained control of Idaho’s open Senate seat as expected, with Lt. Gov. Jim Risch (R) easily defeating ex-Rep. Larry LaRocco (D) to replace retiring GOP Sen. Larry Craig.

The contest amounted to a repeat of the state’s 2006 race for the lieutenant governor’s office, in which Risch defeated LaRocco by nearly 20 points.

According to unofficial state returns Wednesday, Risch claimed about 58 percent to LaRocco’s 34 percent.

In Wyoming, Republicans maintained their stranglehold on the state’s Congressional delegation, sweeping both Senate contests as well as the state’s open at-large House seat.

After defeating Internet entrepreneur Gary Trauner (D) by about 10 points, former two-term state Treasurer Cynthia Lummis (R) will replace retiring GOP Rep. Barbara Cubin.

Although Trauner came close to ousting Cubin in 2006, the incumbent lawmaker was weighted down by her own unpopularity at home as well as national GOP difficulties that cycle — challenges not faced by Lummis.

Sen. Mike Enzi (R) easily won election to his third term over Democrat and college professor Chris Rothfuss (D), claiming more than 75 percent of the vote in the state’s unofficial vote tallies.

Similarly, GOP Sen. John Barrasso took more than 70 percent of the vote in a special election to complete the term of Sen. Craig Thomas (R), who died in early 2007.

Barrasso, appointed to the Senate seat after Thomas’ death, defeated attorney Nick Carter (D) to serve until the seat’s next regular election in 2012.

Incumbents similarly held on in Montana, where Democratic Sen. Max Baucus and GOP Rep. Denny Rehberg easily won re-election to their respective seats.

Baucus won his sixth Senate term with about 73 percent of the vote, according to the state’s unofficial tally, defeating perennial candidate Bob Kelleher (R), who favors changing the federal government into a parliamentary system.

Rehberg will serve a fifth term in the state’s at-large seat, routing former Public Service Commissioner and state Speaker John Driscoll with around 65 percent of the vote.

In Utah, incumbent Reps. Jim Matheson (D) and Rob Bishop (R) easily held their seats, while Republican Jason Chaffetz picked up the state’s 3rd district.

A former gubernatorial aide, Chaffetz knocked off incumbent Rep. Chris Cannon in the GOP’s June primary, clearing his path to victory in the overwhelmingly Republican district.