On the surface, Romney's strength seems at odds with the tea party's fiery success in ousting Republicans seen as compromisers, and in making the House GOP caucus more ideological, even when its leaders plead for flexibility.
Romney defends the government's 2008 bank bailouts, plus the mandated health insurance he initiated as Massachusetts governor. He says he can work with "good Democrats." Although he later changed, Romney once supported abortion rights, gun control and gay rights.
These positions run counter to the beliefs and goals of many tea party activists scattered throughout the country. Yet Romney is faring better in polls, fundraising and debates than are contenders with stronger tea party credentials, including Michele Bachmann, Rick Santorum and Rick Perry.
Several Republican strategists, and even some tea party leaders, say they aren't surprised or alarmed. Their overarching goal is to defeat President Barack Obama next year, they say, and if Romney is best-positioned to do that, they'll endure his shortcomings.
"The perception that tea partyers are ideological purists is wrong," said Sal Russo, a long-time Republican strategist in California and a leader of the Tea Party Express. "We are a broad-based movement," he said, "and we are looking to win in 2012."
Danny Diaz, a Washington-based Republican strategist unaligned with any presidential candidates, agrees.
"The tea party movement is an anti-Washington movement," he said. While Perry and Herman Cain might make a more dynamic claim to that mantle, he said, Romney has never lived in Washington, and tea party activists won't rule him out.
"Many of them are pragmatists," Diaz said. They desperately want to oust Obama, he said, and "they need a candidate that's electable."
A CBS-New York Times poll found that tea partyers are more satisfied with the GOP presidential field than are Republicans in general. Cain was the top choice among tea party activists, with Romney second.
Some campaign veterans see bigger problems ahead for Romney.
Polls of Republicans show Romney holding steady at about 25 percent, while Bachmann, Perry and Cain take turns making surges. "That tells me that 75 percent of the primary voters would really rather have someone else," said GOP lobbyist and consultant Mike McKenna.
Many tea party activists have little or no loyalty to the Republican Party, and McKenna predicts big problems next year if they feel their conservative values were sacrificed for political expediency. "Romney would cause enormous numbers of tea party-type voters to simply not show on game day," he said.
The chief question, he said, "is whether one candidate will be able to aggregate the anti-Romney Republicans before it is too late." Perry seems the likeliest choice, McKenna said, "but the clock is ticking."
Jenny Beth Martin of Atlanta, who is active with Tea Party Patriots, said several groups are having informal talks about whether they should try to coalesce behind an alternative to Romney. Tea partyers cherish their independence, she said, and "over the next eight to 10 weeks, it'll be interesting to see how it all shapes up."
Conservative commentator Rush Limbaugh repeatedly criticized Romney on his radio show last week. "Romney is not a conservative," he said. "The Republican base doesn't want Romney."
For now, Romney seems willing to run some risks, hoping to attract independent voters who will be crucial in the 2012 general election.
In last week's debate in New Hampshire, Romney defended President George W. Bush's 2008 decision to spend billions to rescue banks teetering on collapse, partly because of disastrous home loans. The action was meant not just to save banks, Romney said, "but to keep the entire currency of the country worth something and to keep all the banks from closing and to make sure we didn't all lose our jobs."
Many conservatives despise the bailout, known as TARP, for Troubled Asset Relief Program. In one of their first political victories, tea party activists in Utah chanted "TARP, TARP" at then-Sen. Robert Bennett as they bounced him from the GOP ticket at a 2010 party convention. Bennett, a three-term senator with solid conservative credentials, had voted for the program.
Nonetheless, there was little commentary about Romney's TARP comments after Tuesday's debate, which focused largely on Cain's tax overhaul plan.
It may take hard-hitting TV ads to drive a bigger wedge between Romney and tea partyers, something the well-financed Perry might try soon. Such ads could go into detail, with heavy repetition, about Romney's Massachusetts health care plan, which was a partial model for Obama's 2010 federal overhaul.
Virginia-based Republican strategist Chris LaCivita says the tea party's deliberately decentralized nature makes it ill-suited to play a big role in presidential politics.
"The tea party's strength was always a state-driven or congressional district-driven level," he said. It can continue to influence targeted contests that draw comparatively small turnouts, such as the Utah GOP convention that drummed Bennett out of the party.
Moreover, LaCivita said, the tea party might choke on its own success. If it appears more like the Republican mainstream, he said, it's because tea partyers have shifted that mainstream to the right.
Largely because of their clout in the 2010 elections, LaCivita said, these activists have "changed the conversation, not only among Republicans, but everybody in Washington. Who'd have thought the Democrats would be leading with spending cuts" in deficit-reduction talks?
Those ongoing negotiations, however, could renew tensions between tea party-affiliated House Republicans and the party's more established leaders, including Speaker John Boehner. If presidential candidates are pressed for their views, Romney might find it difficult to keep appealing to independents without antagonizing tea partyers.
The Republican Party "still hasn't resolved all of its ideological internal conflicts," said John Feehery, a top aide to then-Speaker Dennis Hastert, R-Ill. "But they have agreed that they don't like Obama," he said.
Their level of intensity may determine whether Romney can keep prospering against rivals who boast stronger tea party ties.