PITTSBURGH (AP) — Mitt Romney plans to stay on the attack in the race for the White House, but growing pressure from across the political spectrum to release his personal tax returns threatens to stunt the Republican presidential candidate's momentum as he courts voters across key Midwestern battlegrounds.
The former Massachusetts governor takes his fight against President Barack Obama to Ohio on Wednesday, building off fiery speeches in Pennsylvania the day before in which he accused his Democratic opponent of believing the 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 has a series of official meetings in Washington ahead of a two-day Florida campaign swing later in the week.
Democrats have pressed for the release of more of Romney's tax returns and hounded the Republican candidate 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.
On Wednesday, the Obama campaign released a web video questioning Romney's claims that he had "no responsibility whatsoever" at Bain after February 1999, despite SEC filings that 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 television ad released Wednesday that accuses 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 has also seized on comments Obama made while campaigning in Virginia last week.
The president, making a point about the supportive role government plays in building the nation, 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 recently 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 own returns.
A defiant Romney has accused the Obama campaign of using the issue to distract voters from the state of the nation's economy less than four months before Election Day.
But it's unclear if Romney's new strategy will be enough to change the subject, particularly as several prominent Republicans joined Democrats in pushing Romney for more transparency.
Late Tuesday, Texas Gov. Rick Perry — who challenged Romney for the Republican presidential nomination — became the latest in a series of high-profile conservatives 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 urged Romney to release additional tax returns even though it agreed with him that the Obama campaign wanted the returns 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 Gov. Tim Pawlenty, whose name has appeared prominently in speculation about Romney's choice to run for vice president, vigorously defended Romney's limited tax release stance in a nationally broadcast interview Wednesday.
"There is no claim or no credible indication that he's done anything wrong," Pawlenty, who was a two-term governor of Minnesota, said 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."
"I don't think there's any secret to the fact that Mitt Romney has been successful and he's achieved success and he's paid a lot of taxes," he said.
Meanwhile, Romney's campaign was forced to apologize for a supporter's statement that questioned Obama's patriotism, underscoring the political risks associated with the newfound aggression.
In a conference call arranged by the Romney campaign, former New Hampshire Gov. John H. Sununu told reporters he wished Obama "would learn how to be an American."
He later apologized for the remark.
"I made a mistake. I shouldn't have used those words. And I apologize for using those words," he 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."
The Romney campaign concedes that many voters may support the release of his tax returns, but it's unclear whether that's an important enough issue to change their votes.
At the rally Tuesday outside of Pittsburgh, Romney's supporters didn't seem to mind.
"I'm more concerned about what Obama does with my money," said Phil Kearney, a semi-retired 70-year-old Republican from Latrobe, Pa. "Romney's a rich guy. We all know it. God bless him."