Mitt Romney today said that he did indeed ‘go back and look’ at his tax returns and that he never paid less than 13% in taxes in any year over the past decade. Since there is substantial reason to doubt his claims, we have a simple message for him: prove it. Even though he’s invested millions in foreign tax havens, offshore shell corporations, and a Swiss bank account, he’s still asking the American people to trust him. However, given Mitt Romney's secrecy about his returns, coupled with the revelations in just the one return we have seen to date and the inconsistencies between this one return and his other financial disclosures, he has forfeited the right to have us take him just at his word.

A little over an hour ago, Mitt Romney claimed he'd paid at least 13 percent in taxes every year over the last decade—but didn't offer any documentation to back up his claim. The Obama campaign's response:As the GOP's hero Ronald Reagan use to say, "trust, but verify." Actually, I'm not so sure about the "trust" part. And definitely not until Mitt gives us something with which to verify his claim.

I should have noted that the statement was emailed by the campaign and was from Lis Smith, a spokeswoman for Obama for America.