The Minnesota Supreme Court has upheld a 2015 law limiting State Auditor Rebecca Otto's duties.

Wednesday's unanimous decision ends Otto's years of challenges and mounting legal fees. A district court and the Minnesota Court of Appeals had previously ruled against Otto, triggering her appeal to the Supreme Court.

The legal saga began after the Legislature passed a law allowing more counties to hire private firms for annual financial audits. Otto has argued that law was a constitutional breach of her duties that significantly downgraded the state's oversight of county finances.

But the state's high court disagreed. Wednesday's ruling maintained that the law left the auditor's oversight of those private audits intact. A spokesman for Otto did not immediately return a request for comment.