While I dislike Trump, I don't see the big deal with tax returns. Why are they even really necessary to release?
Basic logic calls for the release of tax returns. If a candidate has squeaky clean returns, obviously they'll be released, because it is to their advantage to do so. So anyone who doesn't release them has something harmful to the chances in their returns.
But it goes beyond that. If a candidate has something only a little embarrassing - taking advantage of a legal loophole, or blew some money on a dumb investment, it still makes sense to release returns rather than have voters think it's something worse. After all, they
could be a complete cheat, or lying to the pubic. So they'll release and prove that it's only a small mistake.
And so on down the line - every candidate has an incentive to release their taxes, in order to demonstrate that they're not as bad as they could be. Look at Romeny's "only 14%" and Swiss bank account as an example - that wasn't going to help him with anyone, but not releasing would have implied he was hiding something even worse.
The only candidate with no incentive to release their taxes is one where what's in them is worse than anything the public could plausibly imagine, or where releasing them would utterly destroy their campaign, turning it into a smoking crater.
Until and unless he demonstrates otherwise by releasing them, it's perfectly reasonable to assume that Trump's tax returns prove he is a lying, criminal, bankrupt pedophile who is an agent of foreign powers.
