Gov. Bill Owens’ (R) decision Tuesday not to run for Colorado’s open Senate seat throws the race wide open, and a number of House Members are expected to announce bids in the coming days.

Many state Republicans, including close Owens allies, are quickly turning to freshman Rep. Bob Beauprez as their preferred candidate.

“All eyes are on Beauprez,” said one well-connected Republican.

But without Owens to clear the field, a GOP primary appears a certainty. Rep. Tom Tancredo called National Republican Senatorial Committee Chairman George Allen (Va.) on Tuesday afternoon to inform him that he will enter the race assuming he gets his family’s consent to do so over the weekend.

Former 4th district Rep. Bob Schaffer, who retired to fulfill a term-limit pledge at the end of the last Congress, formed an exploratory committee Monday and will likely benefit from the support of former Colorado Sen. Bill Armstrong (R).

Democrats are growing increasingly optimistic that Colorado Attorney General Ken Salazar will enter the race. Salazar has long been expected to run for governor in 2006 but is growing more and more interested in a Senate bid.

A Salazar spokesman said there is “no hard and fast time table” for a decision, although most Democrats expect him to make an announcement today.

Democrats familiar with Salazar’s thinking maintain he remains undecided about the contest.

“If Ken Salazar gets in the race, then it is very possible that he could clear the field,” predicted Colorado Democratic Party Chairman Chris Gates.

Rep. Mark Udall, a Democrat from Boulder, entered the race late Tuesday night.

Alan Salazar, chief of staff to Udall, who is also weighing a Senate bid, said that the attorney general’s Senate “ambitions have apparently been stirred in the last 24 to 48 hours.”

Ken Salazar and Udall have had “continual conversations” about the Senate race, said Alan Salazar. Democrats indicated there is almost no chance that both Udall and Salazar would make the race.

Alan Salazar also dismissed the prospects of wealthy philanthropist Rutt Bridges, the only announced Democrat in the race.

“Rutt Bridges has never been a serious candidate,” said Salazar. “He helps the [Democratic Senatorial Campaign Committee] out since they have had a lousy fundraising year.” Bridges has said he will not step aside for Udall, and he has been quietly encouraged by some Democratic leaders enthused about the prospect of a self-funding candidate who would not require significant financial support from the DSCC.

Rep. Diana DeGette (D) took herself out of contention Tuesday, saying she will seek a fifth term in her urban Denver 1st district.

Owens’ decision comes just seven days after Sen. Ben Nighthorse Campbell (R) threw the state political scene into disarray by announcing his retirement after two terms.

At a press conference Tuesday, Owens said that “this time is not right for me, my family or for Colorado to make the kind of personal and professional commitment I know I must make to ensure victory.”

He is seen as a potential presidential candidate in 2008 and some close to Owens wondered whether a Senate race, even if successful, would improve his positioning to launch a national campaign. Owens has also been involved in a very public separation from his wife in recent months.

With two giants of Colorado Republican politics out of the Senate race, a bevy of aspiring GOP pols are positioning themselves for the contest.

Leading that list is Beauprez, who is just over one year into his first term representing the suburban Denver 7th district.

Beauprez won the seat by just 121 out of more than 170,000 votes cast and is being aggressively targeted by House Democrats.

Prior to his election to Congress, Beauprez served as chairman of the Colorado Republican Party from 1999 to 2002 and is well liked by the institutional element of the party.

Preparing for a highly contested re-election bid, Beauprez showed $793,000 in the bank at the end of 2003.

If he vacates the 7th district seat, expect a major fight between the two parties in one of the few swing districts left nationwide.

Tancredo, who is one of the most conservative Members of the GOP Conference, is expected to join the race early next week.

First elected in 1998, Tancredo has rapidly emerged as the leading House critic of President Bush’s immigration policies.

Tancredo has also run afoul of Armstrong, whose endorsement propelled him to victory in a contested 1998 Republican primary, because of his decision to break his term-limits pledge and seek re-election in 2004.

Armstrong, an ardent term-limits advocate, served three terms in the House and two in the Senate, leaving elected office in 1990. He has remained extremely active in Republican Party politics, however, and is seen as the leading figure for so-called movement conservatives in the state.

Schaffer said Tuesday that he is “as serious about this race as any race I have been in,” adding that he had already raised a solid amount of money in the first few hours of his exploratory committee.

“There is no doubt that a credible campaign is being waged,” Schaffer said.

Armstrong is likely to throw his support behind Schaffer if the former Member decides to run, said an informed Republican on Tuesday.

Schaffer held the 4th district from 1996 until 2002, when he abided by his three-term-limit pledge and returned to the private sector.

Armstrong did not return a call seeking comment.

McInnis, who is retiring from the 3rd district at the end of this session of Congress, has long coveted a Senate seat and had $1.35 million sitting in his campaign account at the end of last year.

McInnis released a statement saying that he is “still discussing my future with my family and supporters.”

One Republican familiar with the state’s politics predicted McInnis would take a pass on the Senate race and accept a pending job offer from a high-powered law firm. Under that scenario, McInnis could run for governor in 2006 when Owens is term-limited out of office.

Among Democrats, even most insiders admit they are surprised by the interest that Salazar has shown in the race.

“We were pleasantly surprised,” said a national Democratic operative. “We think Ken Salazar would make a very formidable candidate for the U.S. Senate and we would be lucky to have him in the race.”

Salazar has been the state’s top cop since 1998 and won re-election by 20 points in 2002.

In recent weeks he has been involved in a number of high-profile events, including the investigation into rape allegations aimed at members of the University of Colorado’s football team and his office’s release of a detailed analysis of the 1999 Columbine shootings in Littleton, Colo.

Even Republicans admit that Salazar would be a formidable candidate.

“Salazar would be an amazingly strong candidate,” said a GOPer with strong ties to Colorado.

The source noted that Republicans would not be able to tag Salazar as a “Denver liberal” since his roots are in the farming and ranching communities of rural, southern Colorado.