To a certain degree, all this back-and-forth over precisely when Mitt Romney left Bain Capital is an argument about almost nothing. We might reasonably ask, what does it matter? The Romney campaign thought it mattered when they insisted that Romney wasn't part of the firm when it was doing stuff he was being criticized for, like shutting down factories and laying off workers. The Obama campaign thought it mattered when they wanted to make those charges in the first place, and now that they want to keep Romney on the defensive and stretch this story out longer by focusing on things like who Romney was deceiving when he attested on various documents that he either was or wasn't still in charge of Bain during the period between 1999 and 2002. But if we settled this argument once and for all (and don't worry, we won't), would it change much? Not really.
Nevertheless, this whole thing is only going to increase the pressure on Romney to release more tax returns. During the primaries, he released one year's worth (2010), and it turned out to be quite a treasure trove for opposition researchers, more than 200 pages of offshore accounts and lightly taxed income. Part of what's so weird about this question is that Romney seems actually to have believed he could get away with not releasing multiple years. Let's take a look back at what he said in a primary debate in January when he was asked whether he'd do what his father did and release multiple years of tax returns:
In case you can't watch the video, here's his answer to the question of whether he'd do what his father did and release multiple years of tax returns: "Maybe. Ha-ha. Ha. You know, I don't know how many years I'll release. I'll take a look at what the, uh, what our documents are. And I'll release multiple years, I don't know how many years, but I'll be happy to do that." The fake smile and laugh, a Romney trademark, is the tell: He hadn't thought about how to answer this question and ended up giving a noncommittal answer he hoped would make the question go away.
That might have flown during a primary, but if Romney thought he could become his party's nominee and get elected president without releasing returns from other years, he was incredibly naive. So what's in them that he doesn't want people to know about? I agree with Kevin Drum that there probably isn't anything illegal there. After all, that's what he has all those accountants and lawyers for, to minimize his taxes while keeping him on the right side of the law. Though it's possible there's something really shocking hidden in there somewhere, chances are that what we'd learn would just be more details on the Romney finances, which we already know are a kind of intricate financial fractal web whose true complexity you practically need an electron microscope to grasp.
Since Romney's finances are so complex, the release of more tax returns could produce a week or two of stories about all the juicy details, each one reinforcing the idea that Mitt Romney is not just a rich guy but a rich guy who games the system to his advantage and lives in a world most Americans can scarcely imagine. Romney finds that picture unfair; I'd say it's pretty close to the truth. But in either case, I'm guessing that's what he's afraid of.