Eye on 2010

She will run as an opponent of the economic stimulus law enacted in February and a climate change bill -- passed by the House in June and awaiting Senate action -- that includes a "cap and trade" plan to limit industrial emissions that most Republicans oppose.

Norton described health care policies proposed by President Obama and the Democratic-run Congress as a "government takeover of almost 17 percent of our economy through so-called health care reform."

"These all together ensure that we are going to mortgage our children's future unless ordinary people step up to say, 'I'm going to be involved.' And that's why I'm running," Norton said.

She's entering a Republican primary field that already includes several candidates, including Aurora Councilman Ryan Frazier and county District Attorney Ken Buck.

The Democratic Senatorial Campaign Committee, which is assisting Bennet as he campaigns for a full six-year term, issued a statement that said Norton "comes from a world of sticking up for the special interests."

The Democratic party establishment has rallied behind Bennet, who was serving as Denver superintendent of schools when Democratic Gov. Bill Ritter Jr. made him his surprise choice to fill the state's vacant Senate seat. Bennet succeeded Democrat Ken Salazar, who resigned the seat to which he had been elected in 2004 to become Interior secretary in the Obama administration.

But Bennet does not have a clear path in the Democratic nominating contest. He has drawn a challenge from former state House Speaker Andrew Romanoff, who had hoped to be picked by Ritter to replace Salazar in this seat.

CQ Politics presently rates the Colorado Senate race as Democrat Favored, though that rating will be re-evaluated in light of Norton's candidacy and Romanoff's primary bid against Bennet.

To see how the 2010 Senate races are shaping up, check out the CQ Politics' election map.