Washington, DC (LifeNews.com) -- The first skirmish in the Republican presidential primary over the issue of abortion has begun as candidates seeking the GOP nomination vie for the support of pro-life advocates. The campaign of Kansas Sen. Sam Brownback says former Massachusetts Governor Mitt Romney is misleading voters on his abortion stance.

A press release sent to LifeNews.com from the Brownback campaign says the Romney campaign mistakenly said Brownback previously supported legalized abortion.

Brownback's camp quotes from a Romney for President Exploratory Committee statement over the weekend.

"Just like Sam Brownback, Mitt was once pro-choice but changed his views upon being elected to office," the Romney campaign said. "When Brownback was elected to office, that is when he also had a conversion and voted with the pro-life movement."

Dr. Jack Willke, the former president of the National Right to Life Committee says that's not true.

"Senator Brownback has always been pro-life, and has never made a statement or cast any vote to the contrary," Willke maintains.

The Brownback campaign says Romney has switched his position on abortion three times.

It points to quotes starting in 1994, when he campaigned for the U.S. Senate as an abortion advocate, a July 2001 letter to the editor saying he doesn't want to be labeled pro-choice, a July 2005 statement saying he was pro-choice, and his current position, which is pro-life.

"Mitt Romney's flip flops are enough to make John Kerry blush," Brownback for President campaign manager Rob Wasinger said. "It is absurd of Mitt Romney to compare himself to Senator Brownback on the right to life issue."

Romney, who has received the endorsement of prominent pro-life attorney Jim Bopp, says he was officially in favor of legalized abortion until late in his gubernatorial tenure when he confronted the issue of embryonic stem cell research.

During a meeting with Harvard researchers, he said he realized how Roe v. Wade cheapened the value and dignity of human life and he officially converted to the pro-life perspective.

"I am firmly pro-life," Romney told about 100 Republicans at a restaurant campaign stop at the end of last week. "I was always for life."