Mitt Romney, eager to capi­tal­ize on his primary-election victories this week, is aggressively pushing for new donations to offset his presidential campaign’s heavy spending and is erecting battle stations in upcoming Super Tuesday states.

Amid a nominating season that has seen little momentum from race to race, Romney is now trying to build some. His advisers argue that he is finally gaining a meaningful lead, and other Republicans say his triumphs in Michigan and Arizona on Tuesday should quell talk of a late-entering candidate in the race.

“Governor Romney is on track to win the GOP nomination, and it is getting harder to see a path to the nomination for any of his rivals,” Romney campaign pollster Neil Newhouse wrote in a memorandum to reporters Wednesday.

But Romney faces hurdles heading into coast-to-coast contests on Super Tuesday next week. Of the 10 states that will hold votes that day, only three are easy territory for him, while another, Ohio, is a must-win with implications for the general election against President Obama.

Money has become an acute challenge for Romney, who was forced to devote significant resources to fending off Rick Santorum and his other GOP rivals in February. The former Massachusetts governor had less than $8 million on hand at the end of January and has almost certainly burned through most or all of that since then. His campaign spent at least $2.3 million in February just on advertising in Michigan and Ohio, according to a GOP strategist who tracks ad spending.

To sock away cash, Romney has been tacking fundraising events onto his schedule. He raised money in Daytona Beach, Fla., during a visit last weekend to ­NASCAR’s Daytona 500 race. In Michigan, he invited top donors to a reception Tuesday night as the state’s returns were coming in. On Thursday night, Romney will attend a fundraiser in Bellevue, Wash., and he has scheduled major fundraisers in Florida and New York in March. Another major event has been tentatively set for later in the month in the District.

Romney is also soliciting small-dollar donations online. His campaign released a Web video Wednesday urging supporters to make contributions as small as $10 to his “One Term Fund.”

And in his Tuesday night victory speech in Michigan, he made an unusually personal and public plea: “I’m asking for you, by the way, to go on and pledge your support in every way possible.”

Romney is hampered by his heavy reliance on big-dollar donors, including those who have already given the maximum donation of $2,500 to his primary campaign. Just 12 percent of the $63 million that Romney raised through January came from donors who gave less than $200.

‘This slog . . . is costing them’

One top Romney fundraiser, who spoke on the condition of anonymity in order to talk candidly, said the campaign clearly is struggling to cope with a fundraising challenge it didn’t expect to have several months ago.

“This slog they’re in is costing them tons of money,” this bundler said. “They’ve got a fundraising challenge in the sense that they have to keep raising money to keep up with the spending. They’re not in the hole or anything, but it’s a struggle.”

The Michigan and Arizona victories should help spur reluctant donors to get off the fence, though enthusiasm remains a problem, the fundraiser said. “There’s a certain amount of angst on the Republican side about whether in fact Obama can be beat,” he said. “The problem with Romney, which is not a problem that any other candidate has had, is that there’s no passion for this guy. It’s a very mechanical kind of thing.”

Longtime GOP fundraiser Fred Malek, who is raising money for Romney, said there are signs that a growing number of Republicans who had not previously committed to a candidate are coming around to Romney. He said he also expects smaller donors to get more involved as his candidate solidifies his lead.

“There’s an increasing realization that Romney’s going to be the nominee, that he’s eminently qualified and that he’s the best person to beat Obama,” Malek said. “It’s time to get behind him and get this over with so we can contrast with Obama instead of tearing each other apart.”

Looking ahead to Super Tuesday, Romney’s advisers said that while he is fighting to win outright in Ohio, he is also competing for delegates in Georgia, which awards them proportionally by congressional district, even if the statewide popular vote seems out of reach.

“It goes from winning states to winning delegates,” said one senior adviser. He noted that Romney could rack up a healthy delegate total if he gains the most votes in the congressional districts around Atlanta and Savannah, two metropolitan areas expected to give him stronger support than rural parts of the state.

“Were we to go and win Ohio and win Georgia, I think the race would basically be over. I think Ohio is within reach. I don’t know about Georgia,” said a second senior adviser, who, like the first, was granted anonymity to speak candidly about the campaign.

Former House speaker Newt Gingrich is favored in Georgia, his home state, and has campaigned aggressively there in hopes of a comeback.

Concentrating on the Buckeye State

But with 66 delegates at stake, Ohio is ground zero for Romney. His campaign opened a state headquarters a few weeks ago in Columbus, and a cadre of staffers, led by Florida state director Molly Donlin, have decamped to Ohio and are living together in a rented house.

Romney has been courting some of the state’s leading tea party activists while making daily call-ins to conservative talk radio stations across Ohio.

His advisers said he will hammer an economic message around the state. “More jobs, less debt and smaller government” is the slogan emblazoned on banners and trumpeted by the candidate. Romney is focusing on manufacturing, as he did Wednesday morning at a Toledo factory that makes steel fence poles.

Visiting a region that has seen thousands of manufacturing jobs go overseas, Romney tried to project strength in dealing with China, which he said is “cheating” by keeping its currency at artificially low levels to keep the prices of its products down. He said the Chinese have “walked all over” Obama.

“They’ve been able to put American businesses out of business and kill American jobs,” Romney said. “They also steal our designs and our patents and our brand names and our know-how. . . . This president has sat idly by and watched that happen. Oh, he complains. He says he would take them to the mat. But they’ve walked all over him. If I’m president of the United States, that’s going to end.”