Some observers are starting to zero in on 2009 as Romney's problem year, a year in which he may have done a couple of different things.

Matt Yglesias's theory posited in Slate is that Romney was forced, under threat of prosecution, to shut down a secret Swiss bank account that year. Switzerland's largest bank cracked down on secret accounts, and the IRS followed suit, although it allowed holders of such accounts to avoid prosecution by coming clean on their tax-free accounts and paying what they owed.

Josh Green of Bloomberg BusinessWeek speculates that Romney took a big hit in financial meltdown of 2008, maybe a large-enough hit that his losses left him paying no tax for 2009:

As a member of the ultra-rich, Romney probably wasn’t spared major losses. And it’s possible he suffered a large enough capital loss that, carried forward and coupled with his various offshore tax havens, he wound up paying no U.S. federal taxes at all in 2009.

Green notes, intriguingly, that 2009 is the gap year. Romney released his 2010 returns and a summary of his 2011 returns. Before that, he gave the McCain campaign 20 years' worth of returns, and Steve Schmidt said yesterday that as far as he knows there was nothing disqualifying in them. (Although Romney couldn't have given the McCain team his 2008 returns eithers, which would have been filed in spring 2009, so it seems logical that 2008 could be a problem year as well.)

The Swiss idea doesn't necessarily strike me as a nuclear bomb. Pretty bad, all right--he had to pay up in order to avoid prosecution over non-payment of U.S. taxes. But at least he paid what he owed in the end. My sense of how that plays on Main Street is that it's bad but it's the kinds of shenanigans these people get up to all the time and not that shocking.

No taxes, however, would be another matter entirely. Josh Barro of Bloomberg View thinks it's unlikely for reasons he walks through here.

The bottom line, as everyone is saying, is that there must be something deeply unflattering in there. But the tax returns are only one leg of the stool. Let's not lose sight of the other leg--the I-was-CEO-I-wasn't-in-charge-I-retired-retroactively-but-I-still-got-paid leg.

Check out this devastating Obama ad on that point, with regular citizens reading verbatim Romney's explanation. It's terrific. It's gratifying to see the Democrats be better at hardball than the Republicans for a change.

Romney is going to have to release his returns eventually. They must know this in Boston. But oddly, the more speculation builds, the more people will expect there's something really terrible in there, so if there's only something moderately terrible, it might not be such a mortal blow. But then again--it might be.

And finally, there is no better way--no better way--to dramatize the fact that what's legal for rich people to do is not what's right or fair for them to do. We can't get traction talking about these issues during a normal time. So if this is what it takes to have that conversation, fine with me.