Liz Cheney launches U.S. Senate bid in Wyoming

(CNN) -- Liz Cheney, a daughter of former Vice President Dick Cheney,  announced Tuesday she will challenge three-term Republican Sen. Michael Enzi of Wyoming for his seat next year.

"Today I am launching my candidacy for the United States Senate," the married mother of five said in a Web video.

Cheney, who chairs a nonprofit on national security and education called Keep America Safe, sparked speculation of a potential Senate bid in March when she cautioned the GOP against moving too far to the middle after last year's presidential loss.

"It is time for Republicans to get over their loss in 2012. We are all that stands between this president's policies and a damaged and diminished America," she wrote. "It is time to get back in the fight.

"And I do mean fight," she continued in the Wall Street Journal op-ed. "Republicans are being counseled to move the party to the left, but in my experience, those who advocate more liberal policies for the GOP are wrongheaded or Democrats, or both."

The National Republican Senatorial Committee, however, says it stands firmly behind Enzi, the GOP incumbent.

"Our mission is to re-elect our incumbents and build a Republican majority," NRSC Communications Director Brad Dayspring told CNN.

Wyoming is a reliably red state, with a Republican governor, Republican senators and a Republican for its at-large representative in the House. Enzi easily won re-election in 2008 with 76% of the vote.

Former Republican presidential nominee Mitt Romney carried the state with 69% of the vote in last year's election.