Oct. 25, 2011 -- intro: As a two-time GOP presidential candidate, Mitt Romney has been in the national spotlight longer than most of his GOP rivals. And as the country has changed over the 17 years since Romney launched his first campaign, a bid for one of Massachusetts' Senate seats, so too have some of his policy positions.
Whether it is his conflicting comments about Massachusetts health care legislation or his shifting statements on abortion, Romney's rival White House hopefuls have blasted the former Massachusetts governor for changing his tune.
Texas Gov. Rick Perry, for example, has launched two ads attacking Romney for being "misleading" and having "flip-flopped on so many issues." And Minnesota Rep. Michele Bachmann blasted Romney, although not by name, over his stance on abortion, saying in June that it was "not the time for Republicans to put up a candidate who is weak on this issue and has a history of flip-flopping on this issue."
Romney's campaign did not return ABC's request for a comment, but last month Romney said such attacks were "going to happen and I understand it.
"The nature of politics is that you try and find some edge to characterize your opponent and beat him over the head, and that is if you don't have a optimistic or positive message of your own," he said, adding that "in the private sector, if you don't change your view when the facts change, you'll get fired for being stupid."
Here is a look at five issues that Romney has at one time said he supported and at another said he opposed.
quicklist: 1 title: The Flat Tax text: With Perry set to announce a flat tax plan this week, Romney's position on the issue has been called into question.
While Steve Forbes was running for president in 1996 on a flat tax platform, Romney took out ads as a "concerned citizen" that said the flat tax was "a tax cut for fat cats." In 2007 Romney reiterated his opposition to a flat tax, telling the Des Moines Register that "one person's flat tax is another person's unfair tax."
But as the idea of a simplified tax code gains popularity this election cycle, Romney has toned down his criticism for a flat tax, which institutes one tax bracket for all income levels. The GOP front-runner has stopped short of fully endorsing the plan, emphasizing its tendency to raise taxes on the middle class and lower them on the wealthy.
"The flat tax has positive features," Romney said earlier this month at an Iowa town hall. "But then again you have to look and make sure it doesn't raise taxes on middle income Americans."
At a New Hampshire campaign stop in August, Romney said 'the idea of one bracket alone would be even better in some respects," than his multi-bracket proposal, but noted "I want to make sure of this: that we are not going to cut taxes for, if you will, the wealthiest 1 percent."
quicklist: 2 title: Massachusetts Health Care text:
A go-to kicking post for Romney's GOP rivals has been the health care law he signed as Massachusetts governor in 2006.
While Romney consistently claims that he does not support the state law being implemented nationally, in the hardcover version of his book "No Apology," Romney writes "we can accomplish the same thing for everyone in the country."
In the paperback version of his book Romney amends that line to say, "It was done without government taking over health care," a change Romney's spokesman Eric Fehrnstrom said was made after "Obamacare" was signed.
"They were simple updates to reflect that we had more information at the time the paperback came out," said Fehrnstrom.
At the Las Vegas debate last week, Romney said, "It would be wrong to adopt [the Massachusetts law] as a nation. "In the last campaign, I was asked, is this something that you would have the whole nation do? And I said, no, this is something that was crafted for Massachusetts," Romney said.
quicklist: 3 title: Abortion text: Similar to his fellow GOP candidate Herman Cain, Romney's position on abortion has been less than consistent over the years.
While running for governor in 2002 Romney said he supported abortion rights.
"I will preserve and protect a woman's right to choose," Romney said during a debate against his Democratic opponent Shannon O'Brien. "I am not going to change our pro-choice laws in Massachusetts in any way. I am not going to make any changes which would make it more difficult for a woman to make that choice herself."
During his term as governor Romney, vetoed a bill in 2005 that would expand access to emergency contraception. In an op-ed explaining his veto he wrote that he was "pro-life."
"While I do not favor abortion, I will not change the state's abortion laws," Romney wrote.
Six years later, amid is second presidential bid, Romney clarified is current anti-abortion stance, writing in a National Journal op-ed that he supports overturning Roe v. Wade and defunding Planned Parenthood.
"If I have the opportunity to serve as our nation's next president, I commit to doing everything in my power to cultivate, promote, and support a culture of life in America," Romney wrote.
quicklist: 4 title: Don't Ask, Don't Tell text: While Romney has consistently opposed same-sex marriage, his stance on gays and lesbians serving openly in the military has fluctuated.
During his 1994 Senate campaign, Romney sent a letter to the Log Cabin Club of Massachusetts, a gay rights political group, asking for its endorsement and praising "Don't Ask, Don't Tell" as a "step in the right direction."
"I am also convinced that it is the first of a number of steps that will ultimately lead to gays and lesbians being able to serve openly and honestly in our nation's military," Romney wrote. "That goal will only be reached when preventing discrimination against gays and lesbians is a mainstream concern, which is a goal we share."
Then in 2007, while running for the Republican presidential nomination, Romney said he "would not change" the policy.
"It's been the policy now in the military for what 10-15 years and it seems to be working," Romney said at a GOP debate. "This is not the time to put in place a major change, a social experiment in the middle of a war going on. I wouldn't change it at this point. We can look at it down the road."
quicklist: 5 title: Constitutional Amendment Defining Life text: Over the course of this month, Romney has expressed both support and opposition for an amendment that would define life as beginning at conception. Such an amendment would outlaw most forms of birth control.
At a campaign stop in Iowa last week, the White House hopeful said he agreed with the premise of a possible amendment, that "life beings and conception, birth control prevents conception," but said he was "not campaigning for an amendment of some kind."
But two weeks earlier Romney told Fox News host Mike Huckabee that he would "absolutely" support such an amendment.