BOSTON — When he was running for Massachusetts governor in 2002, Mitt Romney's campaign courted voters at a Boston Gay Pride weekend by handing out fliers proclaiming that "all citizens deserve equal rights, regardless of sexual preference."
Just a year later, Mr. Romney emerged as a leading voice against gay marriage, opposing the Massachusetts Supreme Judicial Court's ruling overturning the ban on same-sex marriage.
With Mr. Romney's positions evolving on everything from abortion to gay rights, embryonic stem-cell research to health care, the Republican presidential candidate has faced charges of political opportunism from Republicans and Democrats alike.
In a Web video last month, Texas Gov. Rick Perry highlighted Mr. Romney's shifts on health care and illegal immigration and reminded voters, "You cannot lead a nation by misleading the people."
President Obama's senior strategist, David Axelrod, posed this question to reporters in a conference call last month: "If you are willing to change positions on fundamental issues of principle, how can we know what you will do as president?"
Mr. Romney's answer from last Wednesday's debate: "I think people understand that I'm a man of steadiness and constancy."
To counter the criticism, he said he's been married to the same woman for four decades, has been a member of the same church his entire life and worked at one company for 25 years.
Mr. Romney - who is leading opinion polls in the GOP race - hopes that the argument will help him get beyond what dogged his 2008 campaign.
Still, Mr. Perry and Romney's other rivals portray him as a political chameleon.
Mr. Romney's history offers plenty of fodder, beginning with his gradual about-face on abortion.
During his first foray into politics - a failed 1994 campaign against incumbent Democratic Sen. Edward M. Kennedy - Mr. Romney said that while he was personally opposed to abortion, he thought the procedure "should be safe and legal." By 2005, he had declared himself "pro-life" in an editorial in the Boston Globe.
Of all his past and present positions that Mr. Romney has tried to square, the most public has been his decision to sign Massachusetts' 2006 landmark health care overhaul - a sweeping law that provided a blueprint for Mr. Obama's health care law, the same law Mr. Romney has vowed to dismantle.
Ironically, the "Romneycare" vs. "Obamacare" debate has also provided Mr. Romney with his most succinct retort. Mr. Romney has said the issues of health care should be left to the states, not the federal government.
And on the question of gay rights and same-sex marriage, Mr. Romney has repeatedly pointed out that he never endorsed gay marriage, even during his 2002 campaign for governor.