Republican Mitt Romney often says, as he did at three campaign stops here Thursday, that he wants to create jobs by lowering taxes. He says he wants to loosen federal regulations on businesses. And he says he has a unique skill set from 25 years in the private sector to develop innovative solutions that can revive the sputtering U.S. economy.

What Romney doesn’t say is which taxes he would lower and by how much. He doesn’t say which regulations he would loosen. And he doesn’t say what his solutions are other than general principles that for years have been Republican Party orthodoxy.

It’s not that the former Massachusetts governor doesn’t have ideas. It’s just that he hasn’t shared them yet.

At a lively town hall meeting here Thursday night, Romney methodically plowed through about 15 questions over the course of an hour, including one from a woman wondering whether he would continue to subsidize big oil companies if elected president.

“What I would like to see us do philosophically is to bring our [corporate] tax rates down to be competitive with the world but get rid of a lot of these special breaks that exist,” Romney answered. “We ought to look industry by industry and say, ‘Where are the lobbyists striking special deals for companies?’ Let’s get rid of that stuff and bring our rate down.”

The audience of about 300 gave him a friendly applause and Romney moved on to the next question, leaving behind a slew of unanswered questions. What would the corporate tax rate be? How does he define a “special break”? Which industry loopholes would he eliminate? And, of course, the original query: Would he continue oil subsidies?

By making the economy an almost exclusive focus of his campaign, Romney has raised the expectations for what he eventually will propose and has some policy gurus in his own party openly wondering whether the presidential front-runner has sound proposals to deal with the big problems he says he is uniquely positioned to solve.

“I think at some point he has to say more than just, ‘I’ve got 25 years experience and I’ve done it,’ ” said Steve Bell, a former top policy adviser to Senate Republicans. “Somebody’s going to say, ‘Well, what do you mean you’ve done it? ... Other than just platitudes, what specifically are you going to do to create jobs?’ ”

Bell, now a senior director at the Bipartisan Policy Center, speculated that Romney is “afraid” to offer specifics, adding: “The answers to some of these problems, if you are really rigorously honest about them, are answers that will make the tea party element of the party unhappy.”

Romney’s strategists dismiss that theory, saying he is not trying to cushion himself from scrutiny and that he will release a detailed economic plan once voters are paying closer attention. “Governor Romney will unveil his economic program and his economic policy team in the fall,” senior adviser Eric Fehrnstrom said.

Romney has already begun assembling a team of economic policy advisers, including: N. Gregory Mankiw, who was chairman of President George W. Bush’s Council of Economic Advisers; Glenn Hubbard, who preceded Mankiw on the council and currently is dean of the Columbia University Graduate School of Business; and former Missouri senator Jim Talent.

Romney is slightly more specific in his 2010 book, “No Apology,” calling for simplifying the tax code and reducing rates while eliminating “personal taxes on dividends, interest and capital gains for all middle-income families.”

On the campaign trail, Romney has not yet been pressed to say much more. Unlike some of his rivals, Romney has not participated in many wide-ranging interviews since launching his campaign last month; when he does, they tend to be on friendly terrain. And unlike Obama and congressional leaders, Romney does not hold lengthy press conferences. Instead, he sometimes takes just a couple questions from reporters after events before driving off.

With voters, Romney’s biggest applause lines tend to be his vaguest.

At the town hall, Romney drew a sustained ovation here when he summed his governing philosophy: “The president and a lot of people around him fundamentally believe that really smart people in Washington can do a better job guiding the economy than can free people all pursuing their own dreams. And so whenever they see a problem they look and say how do we put government in there to run things better. And I see a problem and say how do we get government out so we can let free people run things better.”

Most of his leading opponents have been equally vague. Rep. Michele Bachmann (R-Minn.), who has been in the race just a month but is topping the polls in Iowa, also has stuck to broad talking points.

So has former Utah governor Jon Huntsman Jr., also a relatively late entrant, although he has been more specific about his plan to overhaul the federal tax code to eliminate some corporate loopholes while lowering overall rates.

Former Minnesota governor Tim Pawlenty has been the most detailed. He wants to slash taxes and privatize a laundry list of government functions, including Amtrak and the Postal Service.

Under Pawlenty’s plan, laid out in a speech last month, the corporate income tax would drop from 35 percent to 15 percent. He would establish just two individual rates: 10 percent for the first $50,000 of income ($100,000 for married couples) and 25 percent for all income above that. He also would eliminate the capital gains tax, interest income tax, dividends tax and estate tax.

Pawlenty said his plan would balance the budget by 2017. But he is banking on economic growth of 5 percent — a far more bullish estimate than economists project. Some Republican economists called it “impossible” and “totally unrealistic.”

“We welcome the scrutiny,” Pawlenty spokesman Alex Conant said. “Governor Pawlenty took a real risk in laying out a bold and specific plan, but he thought it was important that voters know what he will do when he’s elected president. The other candidates have been very vague in their proposals and either don’t have records or are running away from them.”

Romney’s lack of specificity has become fodder for Democrats, too.

“You get the sense there is a deliberate strategy for him to avoid taking positions so that he doesn’t have to change them later,” said Bill Burton, who now runs Priorities USA, a pro-Obama political action committee that has aired attack ads against Romney.

As Pawlenty learned, big themes often go over better at the early stage of presidential campaigns than gritty details. By sticking to broad scripts, candidates avoid alienating segments of the electorate.

After his campaign bottomed out in 2007, John McCain laid out detailed policies. That helped him regain traction in the race — he won the nomination — but it also drew criticism from some pockets of the GOP.

“There’s no payoff to a lot of specificity up front,” said Douglas Holtz-Eakin, who was McCain’s chief economic policy adviser. “On every campaign, the political guys want all their options open, the policy guys want to lay out policies, and they are in conflict. So the candidate ultimately needs to decide.”