Senator Smith’s decision to retire after just one full term in the Senate scrambled the plans of several ambitious Minnesota Democrats on Thursday, and gave new hope to the GOP that they may be able to expand the map even further next year. The Republicans have already said they will contest the seat in 2026 after not winning a Senate race in the state in more than two decades. 

Ms. Smith, at the age of 66, made the surprising announcement in a post on X Thursday morning, saying that she wanted to retire in order to spend more time with her father and her grandchildren after two decades of serving in public office. She also said that there are plenty of Minnesota Democrats other than her who are capable of serving in the Senate. 

“We have a deep bench of political talent in Minnesota — a group of leaders that are more than ready to pick up the work and carry us forward, and I’m excited to make room for them to move forward,” Ms. Smith said in the video. 

Democrats in the state began moving quickly to solidify their position as potential Senate candidates, at a time when everyone expected Ms. Smith to run for another term. 

On Thursday morning, Politico reported that Governor Walz was considering a run for Senate after his vice presidential bid, eight years as governor, and 12 years as a congressman. Before he could even publicly comment on the Senate race, however, his own lieutenant governor announced she would run for Ms. Smith’s seat. 

“I love Minnesota and my intention is to run for U.S. Senate and continue to serve the people of this state,” Mr. Walz’s deputy, Peggy Flanagan, wrote in a post on X. “I’ll make a formal announcement later this month. In the meantime, I’m talking with community and family and friends. I will have more to say soon.”

There are several other Minnesota Democrats with significant bases of support who also could jump into the race. Congresswoman Angie Craig, who is a Democrat from a swing district just south of the Twin Cities, is considering a run, according to Axios. Congresswoman Ilhan Omar has also not ruled out a run, despite concerns that her hyper-progressive record may be too much even for a blue state like Minnesota. 

One former congressman, Dean Phillips, who famously challenged President Biden in the 2024 Democratic primary on the basis that the president was too old to campaign or do the job, says he will not be a candidate for any Minnesota office in 2026. 

Republicans have not won a Senate election in the state in nearly 25 years, though they say that will not stop them from trying again. When the GOP last won in 2002, the Democratic incumbent — Paul Wellstone — was killed in a plane crash just one week before the election. Democrats chose Vice President Mondale to replace him on the ballot, but he ended up losing to a Republican, Mayor Norm Coleman of St. Paul. 

The National Republican Senatorial Committee has made efforts to win Senate seats in Minnesota in the past, and came within five points of unseating Ms. Smith when she ran for a full term in 2020 after she had been appointed to the Senate in 2017. 

“Minnesota is in play, and we play to win. Minnesotans deserve a Senator who will fight for lower taxes, economic opportunity, and safer communities,” the chairman of the NRSC, Senator Tim Scott, said in a statement Thursday. 

Ms. Smith’s retirement may open a door for the GOP this year, depending on who Democrats nominate, just as Senator Peters’ surprising decision to forgo another run in Michigan may have given Republicans an opportunity. 

The former transportation secretary, Pete Buttigieg, is considering a run for Senate in Michigan next year, despite having lived in the state only since 2020. A recent poll found that he would be the overwhelming favorite to win the Democratic nomination, though another survey shows him losing by six points to the 2024 Republican nominee for Senate, Congressman Mike Rogers. 

Another Senate race that Republicans are keeping their eye on is in New Hampshire, where Senator Shaheen — who would be 80 at the beginning of another Senate term in 2027 — has said she has not made up her mind about whether or not to seek reelection. President Trump’s former ambassador to New Zealand, who also served two years as a senator from Massachusetts, Scott Brown, told a local outlet that he may run for Senate in New Hampshire in 2026, having narrowly lost to Ms. Shaheen in the 2014 race.