Lt. Gov. Michelle Fischbach was sued Friday by a resident of her state Senate district, who argued that Fischbach cannot hold the lieutenant governor's post while also serving as a senator.

Sauk Rapids resident Destiny Dusosky, who has been DFL chairwoman of the St. Cloud-area Senate district, filed the lawsuit Friday. It seeks declaratory judgment on whether Republican Fischbach's intention to hold both seats is unconstitutional.

Dusosky is also seeking a court order prohibiting Fischbach from continuing to hold office representing Senate District 13.

Fischbach is Senate president and automatically ascended to the lieutenant governor position earlier this month, after Gov. Mark Dayton appointed former Lt. Gov. Tina Smith to the U.S. Senate to fill Al Franken's spot.

Fischbach has said she expects the lieutenant governor's job to be largely ceremonial and plans to continue serving in the Senate. She has rejected the salary for her new post.

"Despite the domino effect started by Sen. Franken's resignation, my responsibilities as a senator have not changed. I will act as Lt. Governor as the Minnesota Constitution requires, but I remain committed to serving the people who elected me to the state Senate," Fischbach said in a statement Friday.

When Fischbach initially announced she would hold both posts, Dusosky began to wonder about the potential impacts when the legislative session starts Feb. 20, said her attorney Charlie Nauen. Dusosky wanted to clarify whether Fischbach's votes as a senator would be illegal or not count, he said.

"Destiny Dusosky wanted, at least, to have an effort to have this issue resolved before the session begins, and we're hopeful that will happen," Nauen said. "She thinks the Constitution is pretty clear on this and she wants it straightened out."

Senate Minority Leader Tom Bakk said holding both positions violates the constitutional separation of powers. Minnesota Attorney General Lori Swanson, a DFLer, issued an advisory opinion saying Fischbach cannot legally hold two offices, but that does not carry the weight of a judicial ruling.

"I commend Ms. Dusosky for helping the people of Minnesota get a clear answer from the courts on this obvious conflict of interest," Bakk, DFL-Cook, said in a statement. "Without Lt. Gov. Fischbach's resignation, Senate votes could be called into question. The constituents in Senate District 13 deserve better."

Republicans, however, have pointed to the nonpartisan Senate counsel's opinion that Fischbach can remain in her Senate seat.

The court's decision could temporarily affect who controls the state Senate. If a judge agrees with DFLers and the party wins a special Senate election in February, the Senate would be split 33-33 between the GOP and DFL.

There would be a special election to replace Fischbach if she is removed from her Senate seat.

She has said she would run for her Senate seat and resign as lieutenant governor if she wins.

The lawsuit is disappointing but not surprising, Senate Majority Leader Paul Gazelka, R-Nisswa, said in a statement Friday. He previously pushed for a special session to elect a DFLer as Senate president, so they would become Dayton's No. 2 instead of Fischbach. Senate DFLers rejected the proposal.

"We offered to resolve this dispute before it started by putting another Democrat in the Lt. Governor position to serve alongside Gov. Dayton. This disappointing lawsuit is simply political maneuvering by Democrats to try to change the outcome of the 2016 election," Gazelka said, referring to the DFL losing its majority in the Senate.

Nauen said he did not anticipate that Dusosky would run in a special election if there is one. He would not reveal who is paying her legal costs.