DENVER -- For months, staunch conservatives repeated the same mantra: We'll vote for Mitt Romney, but we're not crazy about him.That's all changed.Thanks to the Republican presidential nominee's aggressive performance in Wednesday's debate, and tough rhetoric Thursday and Friday, the conservative world is embracing a new hero: Romney, derided for years for backing abortion rights, a state-backed healthcare system and other conservative anathemas, is now lauded for standing up to the hated President Barack Obama while vigorously defending the cause of low taxes and smaller government."He'd won their heads. Now he's won their hearts," said David Keene, a former chairman of the American Conservative Union who's the president of the National Rifle Association.Since the debate, conservative radio host Glenn Beck has played Happy Days Are Here Again on his radio show and declared: "Romney looked calm. He looked kind. ... Maybe because he knew Jesus was punching Obama in the face so he didn't have to."Erick Erickson wrote about Romney on his conservative blog, RedState.com, "I may not always agree with him, but at least I know I can trust him to make eye contact with the challenges of our day and set about solving them, not looking for easy distractions and fleeting glories."At the Conservative Political Action Conference, a Denver gathering of about 2,000, Romney got a wild reception Thursday when he made a surprise appearance. Later that day, the NRA announced its endorsement of Romney, even though he signed a ban on assault weapons into law in 2004 as the governor of Massachusetts.Ironically, the conservative outpouring comes while Romney is gingerly scrubbing the right angles off some views.On Monday, he told The Denver Post that he wouldn't overturn Obama's June directive making it easier for certain children of illegal immigrants to stay in this country legally.Romney said previously that he'd look at the issue, and in a January Republican debate he said illegal immigrants should "self-deport."On Thursday night, he told Fox News' Sean Hannity that his assertion that 47 percent of Americans are "victims" overly dependent on government was "completely wrong." For weeks, Romney had refused to back away from the remarks so cleanly.Also being tweaked are his positions on sweeping tax cuts and changes in the healthcare law.During Wednesday's debate, Romney said that although he wanted the 2010 federal healthcare law repealed, he'd continue protection for people with pre-existing conditions. He also repeated his plan to limit itemized tax deductions for the wealthy to offset cuts in income tax rates and ensure that they don't pay any less, a position that drew conservative fire in the Republican primaries.Conservatives seem unbothered by all this now. They feel that Romney has pivoted from the middle before and can easily do it again and that he proved during the debate, when it counted, that he'd stand up to Obama.Karla Kroeker, who runs a natural nutrition product company in Monument, Colo., recalled how Ronald Reagan changed positions on crucial issues such as abortion."As long as Romney is moving in the right direction he'll be fine," she said. "He's articulating conservative values a lot better than I thought he would."This outburst of enthusiasm is crucial to the Romney campaign, which is counting on a committed grassroots effort to mobilize voters, raise money and work the phone banks.For years, conservative skepticism dogged the onetime center-right Republican. He won his 2002 gubernatorial race supporting abortion rights. As governor, he signed into law a near-universal healthcare plan that's regarded as a model for the 2010 federal law that conservatives loathe.Qualms about Romney's record helped boost 2012 Republican challengers such as former Pennsylvania Sen. Rick Santorum and former House Speaker Newt Gingrich. Romney helped himself in August by putting conservative hero Rep. Paul Ryan, R-Wis., on the ticket, but even at the national convention, delegates routinely shrugged when asked their views of Romney.This week, the mood changed dramatically.Conservatives were particularly pleased with how Romney didn't back down, in the debate, from the principles guiding his tax cut and healthcare plans."He was very specific with his ideas, and I found Obama very vague," said Robin Smith, a Denver accountant. "He had the presence of a CEO who could walk into a room and take charge."Romney also spoke the language of conservatives."He talks about liberty, the Founding Fathers and uses other key words that are so big for conservatives," said Marijo Tinlin, author of the book How to Raise an American Patriot.As Leonora Konegen, a stay-at-home mother from Colorado Springs who supported Santorum, said of Romney this week, "That debate sealed the deal for me."