DENVER -- Colorado Attorney General Ken Salazar announced his candidacy for the U.S. Senate seat being vacated by Ben Nighthorse Campbell Wednesday.

Salazar (pictured, left) called news conference on the west steps of the State Capitol to make the announcement.

The two-term attorney general from Alamosa referred to his Hispanic heritage, saying his family's Western roots stretch back four centuries.

"Today I want to help the people of Colorado and our country achieve the same American dream that I have been able to live," Salazar said. "I will do so through my service as a United States senator for the people of Colorado."

Tuesday, U.S. Rep. Mark Udall announced he was running for the Senate seat but backed out of the race Wednesday in order to support Salazar.

"I think maybe this was the shortest Senate campaign in history," said Udall.

Rutt Bridges also bowed out of the race and threw his support to Salazar.

There are four other Democrats in the race: Boulder businesswoman Liz Baker, Denver lawyer Brad Freedberg, Boulder lawyer Larry Johnson, and Mike Miles from the Fountain School District.

When Owens announced he would not run, he said he had encouraged Republican Rep. Bob Beauprez to enter the race. Beauprez had said earlier that he "might" consider running, depending on what Owens decided.

"You've got several people in our party -- myself included -- that might be interested in taking a look at that," he told 7NEWS last week.

Bob Schaffer, a former congressman from Colorado's 4th District, also indicated he might run if Owens didn't. Other Republicans who might run include State Treasurer Mike Coffman and U.S. Reps. Tom Tancredo, Marilyn Musgrave, and Scott McInnis.

The race could be one of the most competitive in the nation and help decide the balance of power in the Senate, where the Republicans hold a 51 to 48 majority.