Former Gov. Mitt Romney (R) of Massachusetts always knew he would have to kick up his presidential campaign up a notch, but it’s happening a little sooner than expected. The reason: the Perry surge.

Suddenly, Gov. Rick Perry (R) Texas is leading polls of GOP voters by double digits, knocking Mr. Romney out of the top spot. Now it’s game on, and Governor Romney is moving out of his comfort zone to address tea partyers – not his natural constituency – and go on the attack (albeit veiled) against Governor Perry.

On Sunday, he will address a tea party rally in Concord, N.H., and the next day, will fly to South Carolina for a candidate forum hosted by the influential Sen. Jim DeMint (R) of South Carolina that Romney had originally decided to skip.

Deep red South Carolina is not considered Romney territory, but its primary is one of the earliest on the calendar, and Romney can’t cede that ground to the other candidates so soon and so easily, says Chip Felkel, a Republican strategist based in Greenville, S.C.

“He can’t lose by 20 points here,” says Mr. Felkel, who is unaligned in the primary. “You’ve got to show the flag a little bit.”

The New Hampshire primary directly precedes South Carolina’s, and if Romney wins in New Hampshire as expected, a poor showing in South Carolina would hurt his momentum.

Romney has visited South Carolina only once this year, and Senator DeMint is an important power broker on the Republican right. He backed Romney in 2008, and has yet to make an endorsement for 2012.

The New Hampshire tea party event is a trickier call. Few self-proclaimed tea party activists back Romney for the nomination, and there’s a chance he may be poorly received by the crowd in Concord. FreedomWorks, a Washington-based group that trains tea partyers, plans to protest Romney’s appearance.

But on balance, it’s a smart move for Romney to address the tea party crowd in Concord, says Dante Scala, a political scientist at the University of New Hampshire.

“The goal for Romney in New Hampshire is not necessarily to win over a lot of those folks, but to make sure they’re not fired up to make Romney their No. 1 opponent,” says Mr. Scala. “To go speak to them at least gives them something to think about, and lets them see Romney in person.”

The one public poll of New Hampshire GOP voters released since Perry entered the race on Aug. 13 shows Romney maintaining his big lead there. And Perry’s big Texas personality may not be a good fit for the more secular, reserved Granite State sensibility. But Romney can’t take any chances with the state neighboring his home base of Massachusetts. If he loses the New Hampshire primary, his campaign is likely over.

“I don’t know that tea party Republicans or tea partyers in New Hampshire are entirely sold on Perry yet,” says Scala. “Both he and tea partyers recognize they’re not an ideal match, but if he can muddy the waters somewhat, it could help.”

Romney, a wealthy former businessman, comes across as more Rotary Club than populist. His biggest black mark among tea partyers is his championing of Massachusetts health-care reform, which includes an individual mandate to purchase insurance – a provision he continues to defend as appropriate for his state, though not nationally.

In addition, the early outlines of Romney’s argument against Perry are beginning to emerge.

“Career politicians got us into this mess and they simply don’t know how to get us out,” Romney said Tuesday in a speech to the Veterans of Foreign Wars in San Antonio, Texas.

He didn’t mention Perry by name, but there was no doubt about what he meant – especially as he spoke on Perry’s home turf.

Romney is running a very different campaign from his effort four years ago. In 2007, he spent early and often, going all out to win the informal Iowa straw poll only to lose the battle that counted, the Iowa caucuses. After he lost the New Hampshire primary to John McCain, he was too weakened to last for more than the next few contests.

This time, Romney has conserved his money and put a lot of effort into New Hampshire and Nevada, another early state where he’s strong.

“I think they’ve been wise in not expending resources early,” says Felkel.