Control of the Minnesota Senate will be on the ballot this November after DFL Sen. Kelly Morrison announced Thursday she will vacate her seat to focus on her campaign for Congress in the Third District.

That will leave the Senate deadlocked at 33-33, with a special election for Morrison's seat deciding control of the chamber. Morrison is resigning early enough in the year to line up a special election with the August primary and November general election, instead of holding it on a separate date. Gov. Tim Walz must issue a writ calling for a special election in the seat.

"Today I am stepping down from my seat in the MN Senate to focus full-time on my campaign for Congress," Morrison posted early Thursday evening on X. "This will save taxpayers the cost of a [separate] special election and allow voters to more easily participate in choosing a new senator. It has been an honor to serve the people of [Senate district] 45."

Morrison, a practicing OB-GYN from Deephaven, is running for the congressional seat currently held by Democratic U.S. Rep. Dean Phillips, who isn't running for re-election.

She has served in the Legislature since 2019, spending her first few years in the House before being elected to the Senate in 2022. Morrison helped lead legislative efforts to protect abortion rights and lower prescription drug costs.

"I will always be grateful to have served alongside Kelly Morrison," DFL Senate Majority Leader Erin Murphy posted to X. "She is a brilliant, thoughtful, strategic leader; aka a powerhouse. The MN Senate is better for her tenure and I'm excited to see her in Congress."

The state DFL and GOP parties, as well as outside groups, will likely pour millions of dollars into the high-stakes special election for Morrison's seat. Republicans who are seeking to flip the state House and end the DFL's trifecta control of state government now have an opportunity to also win the upper chamber.

Morrison easily won the west metro Senate seat in 2022, defeating her Republican counterpart by nearly 13 percentage points. But the seat has been targeted in previous cycles, and half the district is represented by a Republican in the House.

Staff writer Briana Bierschbach contributed to this story.