PITTSBURGH - Mitt Romney, facing heightened attacks by President Barack Obama's campaign for refusing to disclose more of his tax returns, confronts escalating calls from within his own party to put the issue to rest by providing additional filings.
Obama used a new television ad to suggest that the presumed Republican presidential nominee - who has estimated his personal wealth to be as much as $250 million - is hiding something about his finances by withholding to provide more information.
"Tax havens, offshore accounts, carried interest," the narrator of the ad says. "Mitt Romney has used every trick in the book." The commercial ends with: "Makes you wonder if some years he paid any taxes at all."
Romney has released his 2010 tax return and promised to make his 2011 documents public when they are ready, saying that amount of disclosure should be sufficient. He reiterated that position in an interview with the National Review magazine Tuesday.
He said "the opposition research of the Obama campaign is looking for anything they can use to distract from the failure of the president to reignite our economy. And I'm simply not enthusiastic about giving them hundreds or thousands of more pages to pick through, distort and lie about."
As prominent Republicans lend their voices to the Democratic calls for Romney to provide more details of his finances, the former private equity executive is trying to stay focused on his central campaign theme of blaming Obama for persistent joblessness.
Campaigning in the swing state of Pennsylvania Tuesday, Romney accused Obama of believing the government - not business people or workers - deserves credit for American private-sector achievement.
"President Obama attacks success, and therefore under President Obama, we have less success," Romney told several hundred people packed into a warehouse at Horizontal Wireline Services, an oil and gas services company in Irwin. "He wants Americans to be ashamed of success; I want Americans to welcome it, to celebrate it."
Obama, on a $4 million fundraising swing Tuesday in San Antonio and Austin, Texas, told contributors the public had a right to scrutinize Romney's business record, given that he presents it as his prime qualification for the White House. His campaign is pushing to spotlight Romney's years as the chief executive of Boston-based Bain Capital, a company that made business deals with some firms that ultimately closed plants in the United States and shipped jobs overseas.
"Governor Romney - his main calling card for running for office is his business experience," Obama told about 1,100 supporters at the Austin Music Hall who paid $250 to hear him and a performance by country singer Jerry Jeff Walker.
Romney's background, Obama said, involved "investing in companies called pioneers of outsourcing," referring to a Washington Post story that has been used in television ads targeting Romney. "I want to be a pioneer of in-sourcing," the president said.
Joel Benenson, Obama's chief pollster, said Wednesday the Bain and tax return issues speak to "a character dimension" and are fair game for debate.
"It translates into where Romney wants to take the country," Benenson said at a Bloomberg Breakfast with reporters in Washington.
Democrats pressing Romney to reveal more about his tax filings got some help from Republicans - including two of Romney's primary rivals - who said it was time for him to offer up proof he has done nothing wrong.
Texas Gov. Rick Perry and Rep. Ron Paul of Texas, who challenged Romney for the nomination, said Romney should divulge more tax records, adding their voices to former Republican Party national chairman Haley Barbour and commentators George Will and William Kristol.
"The advice I would give Romney is: Who cares about your tax returns? Release them," Barbour told ABC News in a July 16 interview. "We need for this campaign to be about Obama's record."
The Republican-leaning National Review, in an editorial published online after its interview with Romney, echoed that view.
"By drawing out the argument over the returns, Romney is playing into the president's hands," the magazine said. "He should release them, respond to any attacks they bring, and move on."
Presidential candidates have been inconsistent in the past about releasing returns. Obama and Vice President Joe Biden have released 12 years of returns. Sen. John McCain of Arizona, the 2008 Republican presidential nominee, disclosed only two. Former Presidents George W. Bush and Bill Clinton each released eight, while Massachusetts Sen. John Kerry, the 2004 Democratic nominee, provided four.
Ronald Reagan made seven years' worth public and George H.W. Bush disclosed three years. Romney's father, George, released 12 years of returns while running for president in 1968.
Romney's 2010 return showed $21.66 million in income from capital gains, ordinary dividends, taxable interest and other business-related income. He paid an effective tax rate of 13.9 percent, primarily because of preferential treatment of capital gains and dividends.
McCain, who considered Romney as a vice presidential running mate in 2008, said Tuesday he could "personally vouch" that "there was nothing in his tax return that would in any way be disqualifying for him to be a candidate."
"To somehow intimate that, without any basis in fact, is the sleaze campaign that this Obama campaign is running, and it is disgraceful," McCain told reporters on Capitol Hill.
The returns the McCain camp reviewed in 2008 would have pre-dated the financial collapse beginning that year that caused major losses for many wealthy investors, which may have affected their tax rates for several years.
Romney's campaign Tuesday declined to answer questions about how much tax information it is seeking from potential running mates. Spokeswoman Andrea Saul cited the campaign's policy of not discussing the vice presidential search process.
Other Republicans came to Romney's defense. Former New Hampshire Governor John Sununu, a surrogate for him, told reporters in a conference call yesterday that given the volume and complexity of the candidate's filings, providing the 12 years of tax returns Democrats say they want would only offer ammunition for more attacks.
"There will be about six feet of returns in which they can find whatever nit they want to use as a distraction," Sununu said. "There was a movie called 'The Neverending Story,' and I think that issue falls into that category."
-- With assistance from Julie Bykowicz in San Antonio and Roger Runningen, Lisa Lerer, Chris Strohm and Richard Rubin in Washington.