Madison, Wis.

Opponents of Gov. Jim Doyle of Wisconsin spent $4 million on ads last year trying to link the Democratic incumbent to a state employee who was sent to jail on corruption charges. The effort failed, and Mr. Doyle was re-elected — and now the state employee has been found to have been wrongly convicted. The entire affair is raising serious questions about why a United States attorney put an innocent woman in jail.

The conviction of Georgia Thompson has become part of the furor over the firing of eight United States attorneys in what seems like a political purge. While the main focus of that scandal is on why the attorneys were fired, the Thompson case raises questions about why other prosecutors kept their jobs.

The United States Court of Appeals for the Seventh Circuit, which heard Ms. Thompson’s case this month, did not discuss whether her prosecution was political — but it did make clear that it was wrong. And in an extraordinary move, it ordered her released immediately, without waiting to write a decision. “Your evidence is beyond thin,” Judge Diane Wood told the prosecutor. “I’m not sure what your actual theory in this case is.”

Members of Congress should ask whether it was by coincidence or design that Steven Biskupic, the United States attorney in Milwaukee, turned a flimsy case into a campaign issue that nearly helped Republicans win a pivotal governor’s race.