ST. PAUL, Minn. (AP) _ The Minnesota attorney general's office says state Senate President Michelle Fischbach cannot legally keep her Senate seat when she becomes lieutenant governor.

Solicitor General Alan Gilbert issued an opinion Thursday saying an 1898 decision by the Minnesota Supreme Court that Republicans have pointed to is no longer valid. Gilbert says the lieutenant governor's duties have changed since then. But Gilbert notes only a court can decide the dispute.

Fischbach, a Republican from Paynesville, has said she expects to keep her spot in the Senate when she becomes Democratic Gov. Mark Dayton's lieutenant governor. Dayton has appointed current Lt. Gov. Tina Smith to take U.S. Sen. Al Franken's place.

The matter may wind up in court because Republicans could lose their Senate majority if Fischbach has to give up the seat.