After voting for a so-called fetal personhood bill, yet insisting she “always supported abortion being legal under settled U.S. Supreme Court case law,” a Colorado Republican considering a U.S. Senate run told a conservative talk-radio host Tuesday that “I’ve never called myself pro-choice as a politician.”

A progressive blog, Colorado Pols, immediately posted footage of state Sen. Ellen Roberts, who has declared her interest in challenging Democratic Sen. Michael Bennet next year, saying during a 2011 legislative debate that she is a “pro-choice Republican.”

Abortion rights advocates pounced on the inconsistency, saying Roberts can’t be trusted to support reproductive health care.

“Sen. Roberts’ positions and votes on choice issues over the last few years have been erratic at times—even opposing teen pregnancy prevention and sex education programs,” Cathy Alderman, vice president of Public Affairs for Planned Parenthood Votes Colorado, said in a statement. “We no longer consider her to be pro-choice, and understand why she’s having a hard time defining her own ‘label.’ It’s been confusing for a lot of us.”

Roberts told the Durango Herald‘s Peter Marcus that she’d made a “mistake” in claiming never to have been pro-choice.

“I would like to correct my statement from the ‘Dan Caplis Show’ in that I spoke in error when I was on the radio show the other day and said I never described myself as pro-choice,” Roberts said.

“I would like it out there that I made a mistake,” she said. “I should not have used that word ‘never,’ and it’s been a continual learning curve to me in terms of how the labels are attached to people.”

Speaking to anti-choice radio host Dan Caplis on June 2, Roberts not only denied that she’d been pro-choice but also refused to say whether she believed Roe v. Wade was correctly decided.

“That’s an excellent question, one that I’d be happy to try and answer in detail once I decided I was getting into the race,” she told Caplis of KNUS 710-AM in Denver.

Abortion rights advocates said pro-choice voters should be wary of Roberts’ ever-vacillating stance on established abortion law.

“Unlike Sen. Roberts, Colorado voters know where they stand on Roe v. Wade, without parsing or equivocation—they’ve said over and over again at the ballot box we are a pro-choice state,” Karen Middleton, executive director of NARAL Pro-Choice Colorado, said in a statement. “And at a time when abortion rights are under constant assault at the state and federal level, Colorado women need allies we can count on.”

Roberts later decided to answer the question about Roe, telling the Herald that what she “can say with no equivocation is I support abortion being legal under Roe v. Wade.”

State observers have said Roberts’ previous support of abortion rights is a severe liability in winning a Republican primary in Colorado, and her statements on the radio may reflect her concerns about a possible primary fight ahead.

Colorado, along with Nevada, are the only two U.S. Senate contests considered possible pick-up Senate seats for the GOP next year. Nationally, Democrats are defending just ten seats, and seven of those, including Colorado’s, rest in states won twice by President Obama. Republicans will be defending 24 U.S. Senate seats next year.

Efforts by Colorado Republicans to field a strong challenger to Bennet are therefore under the national microscope.

Rep. Mike Coffman, an anti-choice Republican from the Denver suburb of Aurora, was considered the most promising challenger to Bennet. But he dropped out Monday, turning more attention to Roberts, who’d been considered the only other serious candidate to consider a run so far.

Others considered to be possible candidates, but who have not indicated any public interest in the race, are Rep. Scott Tipton (R-Cortez), state Attorney General Cynthia Coffman, state Sen. Owen Hill, state Republican Chair Steve House, and radio host Caplis.

Bennet won election to the U.S. Senate in 2014 in a tight race against anti-choice district attorney Ken Buck, who’s since been elected to the U.S. House of Representatives.