Al Franken is now working to undo a tax controversy that has caused him some damage in the polls paying $70,000 in back taxes to 17 states where he's done business over the years and where he neglected to pay -- a story that has chipped away at his credibility in making the transition from entertainer to politician in a top-tier Senate race.

"What happened is our accountant made a mistake, and all of these are repercussions of that same mistake," said Franken. "His mistake was not understanding the law, the obligation to pay these state taxes."