The resignation of state Sen. Dan Schoen following allegations of sexual harassment has already set off a fierce contest to fill the southeast metro seat he will vacate Dec. 15.

Two former state House members from the area are already in the race, and one of the district's current House members is considering it. The Senate's current 34-33 split between the two parties gives both sides a strong incentive: While the DFL doesn't want to slip further into the minority, Republicans would give themselves a bit more breathing room by winning.

Gov. Mark Dayton is expected to call special elections sometime early next year to fill the seats left open by last week's resignations of Schoen, DFL-St. Paul Park, and Rep. Tony Cornish, R-Vernon Center. Cornish is also leaving under a cloud after facing harassment allegations by several women, and apologizing for his treatment of a lobbyist who said he propositioned her dozens of times over the years.

The scandalous circumstances surrounding treatment of women by both departing lawmakers will give both races potent symbolic power at a time when women in politics are increasingly empowered to speak openly about mistreatment by male colleagues.

But the races — and what's likely to be a more closely contested Senate race in particular — will also be a harbinger of next year's pivotal state elections. They will test the enthusiasm of each party's base, and act as a proving ground for their organizational prowess. Money and volunteers will rush into the races, chasing an unpredictable and likely diminished pool of voters in an unusual midwinter special election.

"It's a springboard, and it creates momentum," said DFL Chairman Ken Martin.

For Minnesota Republicans working closely with the Republican National Committee for the first time in years, the Senate race will be an early test — in a largely suburban district that President Trump won — of whether Republican voters will turn out to support the party despite ongoing struggles to pass their agenda in Washington. Republicans are "working closely with local and national partners to elect a Republican" to the Senate seat, said state GOP Chairwoman Jennifer Carnahan.

"We are looking forward to flipping this Senate district red," she said.

Cornish's district south of Mankato has been strong Republican turf. DFLers have held the Senate seat Schoen is now vacating for more than a decade, but the district has also elected numerous Republican House members during that time.

Both parties have already lined up experienced candidates who are well known both in the district and around the Capitol. DFLer Karla Bigham is a Washington County Board member and former House member from 2007 to 2011. She said Schoen was right to resign.

"He did the right thing for his family and the residents by resigning because he wasn't going to be effective," said Bigham, also a former Cottage Grove City Council member. "I can bring effective leadership back to the Capitol for the residents of the district."

Bigham said she wants to bring change to the Capitol following the scandal: "I think women are going to be part of the culture, and I want to be part of that change," she said.

She touted her work building infrastructure in the district, including county roads and a renovation of Ravine Regional Park. Bigham said she would work for more transportation funding for the district and advocate on behalf of property taxpayers, saying that they have been hit too hard in recent years.

Republican Denny McNamara of Hastings served seven terms in the House, including a stint as chairman of the House Environment and Natural Resources Committee. His family owns a well-known nursery in the area.

"The district is hurting right now," he said. "I think I'm someone who could restore trust in the position."

McNamara said his proudest accomplishments include a deal he helped broker to have the University of Minnesota sell land to the Department of Natural Resources, which reduced student fees while establishing Vermillion Highlands wildlife management area.

He touted his ability to work with the Dayton administration, DFLers in the Legislature, business and labor to cut deals for his constituents and help them when they had trouble with a state agency or a business issue.

Rep. Keith Franke, R-St. Paul Park, said he is considering running and expects to decide by the end of the week. Leilani Holmstadt, who was Schoen's 2016 opponent, could not be reached for comment.

Senate Majority Leader Paul Gazelka said he would leave the decision about a GOP nominee up to local Republicans, but he also made clear he badly wants the party to win the seat.

Last session, when Sen. Carla Nelson, R-Rochester, was missing due to her ailing father late in the legislative session, Senate Minority Leader Tom Bakk, DFL-Cook, used her absence as leverage in key negotiations, Gazelka said.

"It's extremely difficult to navigate through a session at 34-33. It means everyone has to be there every day," Gazelka said.

J. Patrick Coolican • 651-925-5042