Washington (CNN) -- Mitt Romney's twin victories Saturday in Maine and in a conservative straw poll were badly needed bright spots for his campaign at the end of what was perhaps the most humbling week of his presidential candidacy, a five-day stretch that exposed the former Massachusetts governor's frail relationship with conservatives.
One day after dubbing himself a "severely conservative Republican" in a speech to the Conservative Political Action Conference in Washington, Romney won a presidential straw poll of conference-goers with 38% of the vote to Rick Santorum's 31%.
Newt Gingrich and Ron Paul trailed in the distance.
Just hours later, Romney narrowly defeated Paul to win the Maine caucuses, a nonbinding contest in which fewer than 6,000 voters participated.
But if the talk the among conservative activists at CPAC was any indication of what's to come as the Republican race moves into a national phase, Romney's wins Saturday may do little to halt lingering questions about his core convictions or bridge the deepening rift between the party's insurgent and establishment factions.
Santorum supporters were nearly apoplectic in the moments after the CPAC straw poll results were announced, accusing Romney of lying about his conservative record in the conference's main ballroom just 24 hours earlier.
"You repeat a lie often enough, it becomes the truth," said Justin Wight, a political consultant based in Asheville, North Carolina. "That is the Mitt Romney campaign for president of the United States right there."
Judd Saul, a tea party activist and Santorum backer who traveled to CPAC from Cedar Falls, Iowa, said the Republican establishment's fixation on Romney's electability against President Barack Obama is leading the party to an all-but-certain loss in November.
"It is a lie that none of the other candidates are electable," he said. "It is a flat lie. You know who gets to decide who is electable? The people decide. Not the media, not the pundits."
GOP battle lines hardening
Never mind that the straw poll data showed that a candidate's position on the issues was more important to CPAC voters than his chances of defeating Obama -- the battle lines in the Republican presidential race are hardening.
Romney's losses to Santorum in Minnesota, Missouri and Colorado last Tuesday were nonbinding.
But the three states were laboratories of GOP sentiment largely untouched by the blizzard of television and radio ads that swamped airwaves in previous nominating states -- and Romney was firmly rejected by the conservative base in all three.
His stumbles provided Santorum and Gingrich a rationale to forge ahead to the next contests and embrace the hard-line grass-roots fury that has been roiling the GOP since 2009.
Santorum entered CPAC after several days campaigning in Texas, where he drew some of the largest crowds of his campaign.
"As conservatives and tea party folks, we are not just wings of the Republican Party," Santorum declared at CPAC, hours before Romney was set to speak. "We are the Republican Party."
For most of the Republican race, Romney steered clear of fiery talk and cautiously tried to convey an aura of inevitability, keeping the Republican base at arm's length while focusing his economy-themed attacks on the president.
For months, it worked.
In debates and campaign events throughout 2011 and in the early days of this year, Romney's past support for abortion rights and a health insurance mandate in Massachusetts largely escaped attention as the rest of the GOP candidates dueled with each other.
When Romney did come under fire, most directly in South Carolina from Gingrich, the central line of attack focused on his personal wealth and tax returns -- not his evolving positions on core conservative issues.
Tuesday losses expose suspicions
But the suspicions that conservative activists have long harbored toward Romney burst into full view after his losses last Tuesday.
And so the hobbled front-runner came into CPAC grappling with questions about his ideological purity -- the very questions that dogged him in 2008, and the ones he sought to avoid this election cycle when he and his team made the calculation not to compete aggressively in socially conservative states like Iowa and South Carolina.
The day before his address, Romney quietly organized a private session with conservative leaders in a Marriott hotel suite to make them "feel comfortable" about his bid and solicit advice about his message, according to one participant in the meeting.
Then came his speech, a sharp pivot to the right that made clear his campaign is girding for a tougher-than-expected nomination fight, even if it means employing partisan rhetoric that risks turning off the independent voters who will be so crucial in the general election.
Romney said that as Massachusetts governor, he fiercely opposed same-sex marriage, fought for abstinence education in public schools, and vetoed a bill that would have made it easier for young women to obtain abortions.
"I know conservatism because I have lived conservatism," Romney said.
The speech, specifically Romney's claim to be a "severely conservative Republican," left some outspoken voices on the right confused.
"I wasn't quite sure what the word 'severely' meant," said former Alaska Gov. Sarah Palin, who said in an interview with CNN and The New York Times that Romney needs to improve his relationship with tea party activists.
Radio host Rush Limbaugh called the line a "pander."
"I have never heard anybody say, 'I'm severely conservative,'" Limbaugh said on his show. "I've never heard anybody say it."
Legendary conservative activist Richard Viguerie released a harshly worded statement on Saturday casting doubt on Romney's sincerity.
"In my 50 years in conservative politics at the national level, I have never heard anyone other than Governor Romney describe himself as 'severely' conservative," Viguerie said. "Romney has shown, once again, that he can mouth the words conservatives use, but he has no gut-level emotional connection with the conservative movement and its ideas and policies."
Romney is now fighting a war on two fronts: one against the conservatives who appear increasingly hostile to his candidacy, and the other against the Obama campaign, which continues to view Romney as the candidate it would least like to face this fall.
Though Romney's complicated week ended on a high note in snowy Maine, the Obama campaign seemed pleased that its expected opponent is tacking to the right at a moment when he would clearly prefer to be gearing up for the general election.
"There's no doubt Romney has rushed to check off every box on the tea party's litmus test," said Obama campaign spokesman Ben LaBolt.
"But the same lack of trust Romney is facing from many conservatives would be amplified in a general election across the ideological spectrum, because he has taken both sides of so many key issues and said anything to please whatever political audience he is courting," he added.