On Tuesday, conservative US columnist George F. Will offered a new - to me - explanation for Donald Trump's ongoing refusal to release his tax returns.
"Perhaps one more reason why we're not seeing his tax returns is because he is deeply involved in dealing with Russian oligarchs and others," Will speculated in a conversation with Fox News's Bret Baier. "Whether that's good, bad or indifferent, it's probably the reasonable surmise."
The context for Will's comment is a whisper campaign from some Democrats that Russia understands Trump would be better for its interests than Hillary Clinton and, therefore, is orchestrating the leaking of hacked Democratic National Committee emails to damage her. Many experts think that Russia was indeed behind the hack.
Will joins a diverse group who has tried to sniff out the real reason why Trump adamantly refuses to release his tax returns. His official explanation is that he is being audited and to release his tax returns under that cloud would be a major legal gamble or gaffe.
Here's how Trump explained it to Chuck Todd on NBC:
"Every year they audit me. It's routine government. I would never give my tax returns until the audit's finished. But remember this: Mitt Romney, four years ago, was under tremendous pressure to give his tax returns. And he held it and held it and held it, and he fought it, and he, you know, he didn't do too well, okay? But he didn't do anything wrong on his taxes. When he gave his tax returns, people forget, not now."
At this point, there are enough theories out there about Trump's taxes that it's worth cataloguing all of them. Here we go!
1 He has Russian ties.
2 He is being audited.
I mean, maybe. Trump could, of course, release his tax returns even while he is under an audit. Richard Nixon did it in 1973.
3 He did not pay any taxes.
The scant evidence we have on Trump's approach to taxation gives this theory credence. A 1981 report by New Jersey gambling regulators showed that Trump did not pay any taxes at all for two years in the 1970s. How? Because as a developer he was able to report negative income.
4 He has mob ties.
The idea that Trump has links to organised crime has been kicking around for decades. But they've come much more to the fore since he began running for president. Ted Cruz, during a late February interview on NBC brought the accusation into the presidential race: "There have been multiple media reports about Donald's business dealings with the mob, with the mafia. Maybe his taxes show those business dealings are a lot more extensive than has been reported."
5 He donates no - or very little - money to charity.
Again, this is a theory with some meat on the bone. The Washington Post's David Fahrenthold had spent weeks contacting charities in hopes of tracking down the "millions" Trump says he has donated to various organisations over the past seven years. The total amount of charitable giving Fahrenthold found? US$10,000. So ...
6 He is not as rich as he says.
Nailing down Trump's personal wealth is a massive challenge. He says US$10 billion. Others say US$3 billion. Still others insist he is worth far less than either number. Trump takes considerable personal pride in touting his net worth and using it as a blunt instrument to respond to any charge that he has ever failed in life. Tax returns are tough to fudge; they nail down exactly how much you make in a year. Just the raw numbers. It would be hard for Trump to argue his way out of a yearly salary that doesn't befit a billionaire.
I'm not sure which of the theories above is the right one. Or whether the right one is even in the list. But what I do know is that Trump almost certainly is not going to release his tax returns before the November election, making him the first major-party candidate in more than four decades to refuse to do so.