As I've said before if there was nothing for Romney to hide he would have released them already. My guess is he probably didn't do anything outright illegal but what is legal and what is moral and ethical can be very different things.
Using that same distorted logic, Obama is actually a citizen of Kenya and not a U.S. citizen, that he hasn't fully disclosed his ORIGINAL birth certificate, after 5-plus years of campaigning and being in office.
As you know (or should) from my previous posts, I accept that some of the hardest hardliners in the Republican party, including Ann Coulter and the National Review, regard the "birther" issue as unfounded and ridiculous. And I likewise don't buy the "Obama is not a U.S. citizen" argument.
But I'm just making a point about your flawed logic.
Obama was/is playing a game in his limited disclosure on the issue.
And Romney likewise is playing a game to make his opposition look like idiots. Or he just wants to retain some degree of privacy. As I said, John McCain only released his most recent 2 years of tax returns. And the media still vilified MCain as an out-of-touch evil rich guy for it, in a way they did not of *FAR* more rich candidates like John Kerry and Al Gore. The latter two Democrats' unprecedented wealth was never even an issue at any time for the liberal media!
But it sure as hell is for media coverage of Romney, despite that Romney EARNED all of his wealth, and gave away ALL his father's inheritance when it was willed to him on his father's death.
As opposed to Kerry, who passed a hefty boat tax in Massachussetts, and then moored his own boat in another state, bilking Massachusetts out of tens of thousands, on HIS OWN TAX!
Romney has also been far more charitable in his annual contributions than Obama, Kerry, Gore, and Biden. Probably more than all the listed Democrats combined.