Tax troubles that have repeatedly tripped up nominees to serve in the Obama administration have provided rich rhetorical fodder for members of the Senate during confirmation deliberations, prompting an obvious question: How clean are the tax records of the 99 men and women at the other end of Pennsylvania Avenue?

To find out, the online magazine Politico sent a questionnaire to the offices of all sitting senators last week.

As the results have been coming in, Minnesota's Sen. Amy Klobuchar has stood out -- and not in a bad way.

Asked if the Internal Revenue Service had discovered an error in one of her tax returns -- the problem that caused so much heartburn for Treasury Secretary Timothy Geithner -- Klobuchar's staff replied yes: "The senator overpaid taxes in 2003."

Christopher Dodd, D-Conn., is the only other senator who reported overpaying taxes.

Klobuchar, who said her taxes are prepared by an accountant in Minnesota, also said she has never had to pay back taxes.

Of the 56 senators who have so far responded to Politico's survey, six said they have paid back taxes. Thirty senators said that no mistakes have been discovered on their returns and that they've never paid back taxes.

Politico didn't submit the survey to Minnesota Republican Norm Coleman, whose Senate term has expired.

BOB VON STERNBERG