There are no other reasons to keep them under lock and key. Despite his protestations that he's complied with the law, there is a precedent and he will be the first to release only two years. His own father, George, when he ran for the GOP's nomination, released 12 years of tax returns. Others have followed suit.
Mitt Romney: Tax Release Excuses
He claims the Obama camp, and the people of America, we presume he's meant, will want more no matter how many years he releases. But were he to go back to 1999, the year he claims he left Bain while heading up the Salt Lake Olympic bid, and release his returns from there forward, that would quell the hounds. Releasing 1999-2009 would satisfy precedent and more than suffice and his mumbling anything to the contrary is an attempt to deflect from the issue and speaks to his honor as a candidate for his country's highest office.
He's also claimed he does not want to give fodder to the Obama camp, for fear they will lie and distort. But the American people will decide on the basis of his returns what to think about his financial life, they are not puppets of the Democrats, if they were the election would already be decided. If the fact the opposition will get the information were an argument not to release it, all candidates in political elections would refuse to release all manner of details, not just their tax returns. "The other side will distort them," would be the cry forever heard.
Romney afraid to release taxes
If his returns have nothing of controversy, no proof he was part of Bain's outsourcing decisions, no arrows pointing to secreted money in off-shore accounts, or other issues, that will be the end of it. But despite the fact he and his camp are aware this won't go away until he releases them, and so have every reason to release them, they won't. They won't because there is something in them that will do a better job of damning his candidacy than not releasing them already is.
And finally, not releasing taxes speaks to his moral ground, and it's a dangerous area for him to try and bypass. Edward D. Kleinbard, a professor at the Gould School of Law in Southern California, spoke to that issue in a piece he wrote on CNN
"What the American people deserve is a complete and honest presentation by Romney of how his wealth was accumulated," Kleinbard wrote. "Where it is now invested, what purpose is served by all the various offshore vehicles in which he has an interest and what his financial relationship with Bain Capital has been since his retirement from the company.
"These are all factors that go to the heart of his character and values."