Obama's SuperPAC, Priorities USA, has taken a lot of flak for some of its recent television spots. Now, in a new ad, the campaign itself has accused Romney of intimate financial involvement in one of "the largest tax avoidance schemes in history." As its narrator puts it, “We do know that Romney personally approved over $70 million in fictional losses to the IRS as part of the notorious ‘Son of Boss’ tax scandal,” the narrator says, “Isn’t it time for Romney to come clean?” The accusation centers on Romney's role as an auditor for Marriott International in the 1990s, when the hotel chain was successfully accused of using a complicated tax shelter.