There, there, Mittens has nothing to hide. We know because he says so, and we know he never lies, haven't you been listening to the things he says. He'll prove there isn't anything untoward in his tax returns, by not releasing them. We already know he's rich, so what is he hiding?
He says Republicans want us all to be rich (unlike those Democrats). I personally would like to know how to turn a few tens of thousand of dollars into tens of millions of dollars, all tax free. Who ever made those profits possible by taking a tens of millions loss almost certainly wrote it off those losses on their taxes. That's what he's hiding. The IRS recently gave amnesty from criminal prosecution to people who used off-shore tax havens to do tax fraud, if you paid the tax and penalties. He could be hiding that sort of thing. Something is in those returns that would guarantee he'd lose the election, if not go to prison.
Brad Friedman (the voting machine blogger, Bradblog.com) is certain that Mittens is hiding proof of his voter fraud when he claimed he was living in his son's unfinished basement in Massachusetts to vote against Kennedy, because he was filing taxes in California. I don't think so, he would never be prosecuted for that, he's a rich Republican. He bragged about doing it. The statute of limitations has probably run out, besides most people don't even think voter fraud is a crime, if you're white.