(CBS News) WASHINGTON - Mitt Romney said Tuesday he will not release more than two years of his income tax returns, arguing that President Barack Obama's campaign would just use material to distort and lie about his record.
Still, some Republicans think that releasing more returns would help Romney. Texas Gov. and former presidential candidate Rick Perrywould be a good idea for the GOP candidate.
"I'm a believer that no matter who you are or what office you're running for, you should be as transparent as you can be with your tax returns and other aspects of your life so that so people have the appropriate ability to judge your background," Perry said.
The Obama campaign continued to ramp up the pressure on Romney Tuesday. The former Massachusetts governor was greeted in Irwin, Pa. Tuesday by a withering new ad from the Obama campaign about Romney's refusal to release more of his past tax records.
"Makes you wonder if some years Romney paid any money in taxes at all," the ad says.
Romney did release his 2010 returns back in January after much prodding from his Republican primary rivals. In one debate, former House Speaker Newt Gingrich said "the idea that you could run for president and not release your taxes in an absurdity."
The returns showed Romney paid an effective 13.9 percent income tax rate on nearly $22 million in income.
He got an extension to file his 2011 returns and has promised to make them public when they're completed.
But a growing number of Republican leaders are advising him to release more, if only to put the topic behind him.
"It was quite a number which we released," said Indiana Sen. Richard Lugar, who ran for president in 1996. He added it would be "prudent" for Romney to release more years of his tax returns.
"I have no idea on why he has restricted the number to this point," Lugar said.
President Obama released six years of tax returns during the primaries in 2007. Former President George W. Bush released nine years when he first ran. But President Obama's former challenger, Sen. John McCain, released two years and told CBS News Tuesday "that's good enough for Romney, too."
The Arizona senator said the Obama campaign's tax return demands are a distraction. "That's exactly what the Obama campaign wants to do, is create a distraction. Anything to avoid the economy that's in the tank."
Even Newt Gingrich now backs Romney on this issue.
"Well, I thought he owed it to the country to share more," Gingrich said. "He's agreed now to go to two full years of disclosure. At the time, he hadn't done that."
But he had this advice for the Romney campaign.
"I think they've got to be tougher and more direct and I think they will be," Gingrich.
Part of the challenge for Romney is that it was his own father, George Romney, who set the standard from presidential candidates when he released 12 years of tax returns while he was running for president in 1968.