Rick Santorum and his supporters moved quickly Wednesday to raise money and redirect their efforts after a surprising Tuesday sweep of three contests again put the former senator from Pennsylvania in position to contend for the Republican nomination.

Santorum held a fundraiser in Texas on Wednesday and plans to do the same in Oklahoma on Thursday. His campaign reported raising a quarter of a million dollars after his victories in Minnesota, Missouri and Colorado.

Santorum is focused on making major pushes in the Feb. 28 Michigan primary and in Ohio on March 6, where his campaign believes his blue-collar roots will match up well against front-runner Mitt Romney.

Without the money or organizational structure of Romney’s campaign, Santorum is taking a stand in states that are likely to respond to his socially conservative everyman message to avoid a repeat of his experience after Iowa, when a similar bounce evaporated quickly in New Hampshire against a superior organization in a moderate state.

“We are smart enough to know that this is no time to celebrate,” said John Brabender, a senior strategist for Santorum. “Tuesday night expanded the playing field. The more you have success in states, the less dependent you are on ads. And people are paying attention. But we have to pick our battles.”

Stuart Roy, a spokesman for an independent group supporting Santorum, said officials spent Wednesday taking calls from donors and adding new states to their target list for this month and for Super Tuesday contests on March 6.

“We are taking a hard look at states that may have previously been viewed as completely uphill,” he said.

Roy would not cite specific states, but he said that “a couple of the Southern states are in play since Romney’s Northeastern politics don’t play well there. And although Gingrich may look a bit like Paula Deen, politically he’s no Southerner.”

Those states are likely to be Georgia and Tennessee. The only other Southern state to hold a contest between now and Super Tuesday is Virginia, but Santorum failed to qualify for the ballot there.

In a sign of what’s sure to come, Romney went on the attack Wednesday, painting both Santorum and Newt Gingrich as Washington insiders.

“Newt Gingrich and Rick Santorum, they’ve spent a lot of time in Washington. And during their years, we spent more money than we were taking in,” Romney said at a campaign stop in Atlanta. During Santorum’s years in Washington, Romney continued, “the government grew by 80 percent, and he voted to raise the debt ceiling five times.”

Santorum said Wednesday that he’s been steadily collecting money over the past two weeks to fight back against Romney and that Tuesday’s results show he can withstand an onslaught.

“Mitt Romney is saying that I’m not a conservative,” Santorum said Wednesday morning on “Fox and Friends.” “That’s almost laughable for a moderate Massachusetts governor who’s been for big government programs. . . . Look, we’ve got the best record, and he’s just going to have to live with that record, and we’re going to make it a part of this campaign.”

Santorum also sought to make the case that his win in Missouri, where Gingrich failed to qualify for the ballot, showed that he can beat Romney in what was essentially a one-on-one match-up. Santorum won 55 percent of the vote there, more than double Romney’s 25 percent. Rep. Ron Paul (Tex.) came in a distant third.

But Santorum’s wins Tuesday came in part because he was able to devote significant personal attention to a trio of low-turnout races on which Romney and Gingrich had both made clear they intended to spend less time.

In the nine days since Santorum was briefly forced off the campaign trail just before the Jan. 31 Florida primary to be with his hospitalized daughter, he spent almost all his time in the three states that voted Tuesday, wagering that winning there would revive his lagging campaign, even though no delegates were technically awarded in the contests.

“Much of Santorum’s success came from just showing up — investing the time in the strategy to pull off this type of victory,” said Republican strategist Ron Bonjean. Also difficult to repeat will be a confluence of other factors, some designed and some coincidental, that led to Santorum’s sweep.

In recent days, Santorum accumulated a slew of endorsements from conservatives who have embraced the idea that he presents the strongest contrast with President Obama.

They include Michelle Malkin and David Limbaugh, conservative authors and pundits; Rep. Tom Tancredo (R-Colo.), a former presidential candidate; and James Dob­son, the founder of Colorado Springs-based Focus on the Family.

Romney spent limited funds in the three states to preserve his cash advantage for the bigger ­races to come. Only in the past few days did he begin training on Santorum the kind of firepower he’s reserved in recent weeks for Gingrich. Santorum benefited from the Romney-Gingrich slugfest that left some voters with a poor impression of both, but he will probably have to join those battles in coming weeks.

“There is a segment of the Republican Party who wants anyone but Romney. And Gingrich wasn’t looking like he was the right guy. This was a process of elimination as much as it was a process of attraction,” said Katy Atkinson, a Denver-based GOP consultant, noting that none of the candidates had a strong ground game in Colorado.

And Santorum’s decision to abandon campaigning for 48 hours just before the Florida primary to be with his 3-year-old daughter — who has a congenital condition called Trisomy 18 that can make a simple cold potentially deadly — might have helped remind social conservatives of his strong stand on their issues.

Santorum has made his personal story as a father of seven central to his campaign and often talks about his daughter Bella as a symbol of his opposition to abortion, because some couples who learn that a child will be born with the fatal condition end the pregnancy.

“I think it really humanized Rick Santorum as not just an everyday politician but a family man,” Bonjean said. “That really hit home, especially at a time during the standard political season, where you had a lot of mudslinging. . . . It was really noticed, especially by a lot of conservative American families.”

Henderson reported from Ohio. Staff writer Felicia Sonmez in Atlanta contributed to this report.