The excitement surrounding Colorado’s newly wide-open Senate race is sure to trickle down the ballot, shifting extra national attention — and money — to the Centennial State’s House races as well.

With six of the state’s seven House Members at least looking at the Senate contest as the week started, lines of would-be successors have already started to form.

But Rep. Diana DeGette (D) frustrated a host of ambitious Denver Democrats by announcing Tuesday that she would seek a fifth term in the House rather than run for Senate. Rep. Joel Hefley (R) had previously said he was not interested in a Senate race.

Still, the situation in Colorado is so fluid that some political operatives say it is too early to predict what Colorado’s House landscape will look like.

“There is a whole lot of speculation about people running” for Senate, said Carl Forti, communications director for the National Republican Congressional Committee. “Ultimately, I don’t think a lot of them will pull the trigger.”

No matter what happens, Colorado is already the site of one competitive open-seat House race. Rep. Scott McInnis (R), now among the Members looking at running for Senate this year, announced his retirement several months ago.

Seven Republicans are running to replace him, with former state Department of Natural Resources Secretary Greg Walcher the early frontrunner. State Rep. John Salazar — brother of Colorado Attorney General Ken Salazar (D), also among the elected officials looking at the Senate race — is the heavy Democratic favorite.

Whether John Salazar would be at all affected by a Ken Salazar Senate candidacy remains to be seen. Although McInnis’ sprawling 3rd district votes Republican in presidential elections, party registration is even, and Democrats believe they can win there.

The Republican field may not be set either. There is some talk that if Dan Corsentino, the scandal-scarred Pueblo County sheriff, gets out of the race, then state House Speaker Lola Spradley, who shares the same Pueblo base, may get in it.

Meanwhile, Republicans’ tenuous hold on the tossup 7th district in suburban Denver could take a turn for the worse if freshman Rep. Bob Beauprez (R) runs for Senate.

Although Beauprez won his seat by just 121 votes in the closest Congressional election of last cycle, he is the slight favorite to retain it over Jefferson County District Attorney Dave Thomas, a two-time loser in Democratic Congressional primaries.

Although Democrats like Thomas, his fundraising has been sluggish so far, and there is some talk that a more heavyweight candidate would jump into the race if Beauprez makes a statewide bid. The name most often mentioned is state Senate Minority Leader Joan Fitz-Gerald (D), though former state Sen. Ed Perlmutter (D), who has declined entreaties to run for the seat in the past two cycles, may be persuaded to take one last look.

On the Republican side, Rick O’Donnell, who was runner-up to Beauprez in the 2002 House GOP primary, is likely to run if the Congressman moves on. O’Donnell, who runs the Colorado Department of Regulatory Affairs, is close to Gov. Bill Owens (R) and is friendly with Beauprez despite their hard-fought battle two years ago.

Regardless of the candidates at the starting gate, the 7th, as a purely swing district, is sure to get plenty of attention in the Senate race, and whatever political resources are poured into the district will affect the fates of the House contenders.

“Beauprez running [for Senate] is good for us, but we’re going to compete in that district anyway,” said a national Democratic strategist.

In the adjoining 6th district, where Rep. Tom Tancredo (R) looks increasingly likely to run for Senate, state Treasurer Mike Coffman (R) is poised to jump in, though he too is looking at the Senate race. Coffman caught a huge break this week when state Senate President John Andrews (R), who is term-limited, announced that he would not run.

Colorado Democrats are high on their likely nominee in the 6th, businesswoman Joanna Conti, but the district is so overwhelmingly Republican that even in an open-seat scenario, she is a long shot at best.

In the Boulder-based 2nd district, with Rep. Mark Udall (D) still agonizing at press time about whether to get into the Senate race, half a dozen Democrats are taking a serious look at trying to succeed him. Those most frequently mentioned are Fitz-Gerald, who lives in the 7th district but has three-quarters of her Senate district in the 2nd; state Sen. Ron Tupa; and state Board of Education President Jarred Polis.

Polis, a multimillionaire high-tech entrepreneur in his early 30s, spent about $1 million of his own money to win his seat in 2000, narrowly defeating a Republican incumbent who spent in the neighborhood of $10,000.

Also mentioned as possible Udall successors: wealthy Boulder businessman Rollie Heath, who took just 34 percent of the vote as the Democratic gubernatorial nominee in 2002 (he did not self-fund); state Rep. Alice Madden (D); and state Sen. Terry Phillips (D), the unsuccessful Democratic nominee for state treasurer in 2002.

The Republicans have no obvious strong contenders in a district that would have given Al Gore and Ralph Nader a combined 57 percent of the vote in 2000. Some party leaders may try to enlist former Boulder Mayor Bob Greenlee, who took 47 percent of the vote against Udall in the Congressman’s first election back in 1998.

The two female Members of the Colorado delegation have also expressed some interest in running for Senate. But DeGette pulled out of the race on Tuesday, and freshman Rep. Marilyn Musgrave (R) is considered unlikely to run if Tancredo or her predecessor, former Rep. Bob Schaeffer (R), make the race. The seat in the Denver exurbs and Colorado plains is almost certain to stay in Republican hands regardless of what she does.