PITTSBURGH — Mitt Romney plans to stay on the attack in the race for the White House, but mounting pressure on the Republican presidential candidate to release his tax returns threatens to stunt his momentum as he courts voters across key Midwestern battlegrounds. The top Republican on Capitol Hill defended Romney on Wednesday, saying the campaign is "not about tax returns, it's about the economy."
Romney was taking his fight against President Barack Obama to Ohio on Wednesday, building off fiery speeches in Pennsylvania the day before in which he accused the Democrat of believing government is more vital to a thriving economy than the nation's workers and dreamers.
"I'm convinced he wants Americans to be ashamed of success," Romney declared Tuesday in the Pittsburgh area as hundreds of supporters cheered him on.
Having spent most of Tuesday courting donors across Texas, Obama was spending Wednesday at the White House before beginning a two-day campaign swing through Florida. His wife, first lady Michelle Obama, was speaking at a campaign fundraiser in Birmingham, Ala.
Democrats have pressed for the release of more of Romney's tax returns and have hounded him over discrepancies about when he left his private equity firm, Bain Capital. Obama has been trying to keep Romney focused on matters other than the sluggish economy, even releasing a single-shot TV ad Tuesday that suggests Romney gamed the system so well that he may not have paid any taxes at all for years.
House Speaker John Boehner, Ohio Republican, took a rare step into the presidential race Wednesday, telling reporters in Washington that Obama's criticism of Romney's career and taxes are meant to distract from the administration's handling of the economy.
Boehner said Obama's questions are an "attack on the private sector" and show that the president "doesn't give a damn about middle-class Americans who are out there looking for work."
Boehner also warned those, including fellow Republicans, who are calling on Romney to make more of his tax returns public.
"The American people are asking, 'Where are the jobs?' Boehner said. "They're not asking where the hell the tax returns are. It's not about tax returns, it's about the economy."
Obama's campaign released a web video Wednesday questioning Romney's claims that he had "no responsibility whatsoever" at Bain after February 1999, when Romney says he left the firm. SEC filings list him as sole owner and CEO through February 2001.
After being on his heels for several days, Romney launched an aggressive counterattack this week, punctuated by biting speeches, conference calls and a TV ad Wednesday accusing Obama of "crony capitalism." The ad says Obama sent stimulus money to "friends, donors, campaign supporters and special interest groups" and charges that taxpayer dollars went to projects in Finland and China.
Romney also has seized on comments Obama made last week in Virginia.
Making a point about the supportive role government plays in building the nation, the president said, in part: "Somebody helped to create this unbelievable American system that we have that allowed you to thrive. Somebody invested in roads and bridges. If you've got a business, you didn't build that. Somebody else made that happen."
Obama later added: "The point is, is that when we succeed, we succeed because of our individual initiative, but also because we do things together."
At a Pittsburgh fundraiser Tuesday evening, Romney lashed out at the remark, a strategy his campaign says will be a theme for the week, if not longer.
"It's foolish on its face and shocking that a president of the United States would not understand the power of entrepreneurship and innovation," Romney said. "It is an attack on the very premise that makes America such a powerful economic engine."
For the often-reserved Romney, the fresh attacks marked a substantial escalation in aggression for a candidate who has struggled to answer questions about his business career and personal tax returns. The former businessman, who would be among the nation's wealthiest presidents if elected, has so far released just one year of personal income tax returns and promised to release a second.
That's a stark deviation from a tradition created in part by Romney's father, George, a presidential candidate a generation ago who released 12 years of his returns.
A defiant Romney has accused the Obama campaign of using the issue to distract voters from his handling of the economy less than four months before the Nov. 6 election.
But it's unclear if Romney's new strategy will be enough to change the subject. Several prominent Republicans joined Democrats in pushing Romney for more transparency.
Texas Gov. Rick Perry — who challenged Romney for the GOP nomination — became the latest top conservative to pressure Romney to open his finances. Perry, who has released his tax returns dating back to 1992, said anyone running for office should make public as much personal information as possible to help voters decide.
The conservative National Review also urged Romney to release more tax returns even though it agreed with him that Obama's camp wanted them for a "fishing expedition."
"By drawing out the argument over the returns, Romney is playing into the president's hands," the magazine said in an online editorial. "He should release them, respond to any attacks they bring, and move on."
Romney spokesman Kevin Madden said Romney will not bow to the pressure.
"The governor has gone above and beyond what's required for disclosure," Madden said. "The situation remains the same."
Former Minnesota Gov. Tim Pawlenty, who features prominently in speculation about Romney's choice for a running mate, vigorously defended Romney's limited tax release.
"There is no claim or no credible indication that he's done anything wrong," Pawlenty said Wednesday on "CBS This Morning."
Pawlenty accused Obama's campaign of "hanging shiny objects before the public and the press, and the press is taking the bait."
Romney's wife, Ann, meanwhile, shed some light Wednesday on her husband's vice presidential search. A top aide to the candidate earlier had suggested that an announcement could have come by the end of the week.
In an interview with ABC News, scheduled for broadcast Thursday, Ann Romney said her husband had yet to settle on a candidate.
"We're not quite there yet," she said, according to excerpts released by the network.
Separately, Romney's campaign was forced to apologize after a supporter questioned Obama's patriotism.
In a conference call Tuesday arranged by the campaign, former New Hampshire Gov. John H. Sununu told reporters he wished Obama "would learn how to be an American." He later apologized.
"I made a mistake. I shouldn't have used those words. And I apologize for using those words," Sununu told CNN. "But I don't apologize for the idea that this president has demonstrated that he does not understand how jobs are created in America."