So this entire post is based on that informed speculation. If it definitely turns out it's not Huntsman or the other Huntsman, well, this is a fun game to play anyway.
So here we go:
Harry Reid is chatting with his old friend Huntsman Senior, who has just the craziest story to tell. You see, the Huntsmans have joined most of the country in deciding that Mitt Romney is a dick, or maybe they were pioneers in that sentiment (the Huntsmans have long known the Romneys). Heck, there may even be some behind the scenes church politics we're not privy to. But whatever the motivation, Senior has quite the story relayed by the guy who worked the finances at Bain Capital ... former managing director Robert C. Gay and current Huntsman business partner. How serendipitous!
It turns out, claims Huntsman, that Romney didn't pay taxes for a decade. What a ludicrous story! Who could believe it? And Huntsman doesn't want to go public with it.
Reid obviously wants to damage Romney, and knows this story would put the Republican nominee in a bind. If true, he can't release the taxes, but every day he refuses to release them is another day that Romney takes a hit with the voters.
So he knows he won't make the safe play and sit on the story.
Still, he's got something else to protect in addition to his source: his reputation. He's probably not worried about reelection at this point, not just because he's got four years until his next one in a state that is trending strongly Democratic, but because he'll be 76 then and may want to call it quits. He knows the media will crucify him for making such outlandish accusations without concrete proof because, you know, he's a Democrat and Democrats don't play dirty.
But he trusts Huntsman. But better yet—Huntsman is a well-known recognizable name with a great deal of cachet outside Republican crazy circles. There's a reason Junior was President Barack Obama's ambassador to China. So Reid is confident his accusations are true. But better yet, he knows that if the identity of his source is revealed, the Huntsman name will instantly add credibility to his claims and damage Romney even further. This isn't some random scrub, after all.
So he goes public and crosses his fingers that the Republicans will take the bait—if they ignore him, his gambit goes nowhere. No need to worry. They instantly ramp up the outrage meter from 0 to 11.
Now the biggest threat to Reid's credibility, other than to be proven wrong by having Romney release his taxes (which would certainly be a Phyrric victory for the GOP), would be having his source never revealed. If the mystery of the source is never solved, he'll have a perpetual cloud hanging over his good name—the possibility that he willfully disseminated a lie in order to smear his political opponents. While Republicans celebrate that kind of politics, it generally embarrasses liberals.
He needs his source revealed, so he starts dropping a hint here, another hint there. He lets the story simmer, one news cycle after another. He gets CNN's Dana Bash to vouch for his source. Eventually, he figures, people will figure it out, and when they do, the story will fully explode and he'll be vindicated.
Meanwhile, Romney will have spent weeks trying to fend off the tax return attacks, only to find himself in the tightest bind—wage a he-said, she-said battle against a man whose reputation he'll never equal, or cave on those tax releases. Either way he loses, Democrats win, Harry Reid carries the day.
And we promote Reid from Democrat of the Week, to Democrat of the Year.