Gov. Mark Dayton delayed naming a new U.S. senator for Minnesota on Friday, as attention focused on the DFLer said to be his likeliest choice: Lt. Gov. Tina Smith.

Dayton said Friday morning that he would name a replacement for Sen. Al Franken "in a couple days," declining to be more specific, and not mentioning any names. Smith, who dropped out of a public appearance Friday and several scheduled for early next week, declined interview requests.

A Democratic operative who's been privy to Smith's thinking told the Star Tribune that if Dayton picks her, she has not ruled out running for Franken's seat in a special election in 2018 — and, if she wins, running again for a full six-year term in 2020.

For U.S. Senate Democrats in particular, Dayton's appointment could provide the party an important head start in holding on to Franken's seat with a 2018 national Senate map that favors Republicans.

Dayton has had a couple conversations with Senate Minority Leader Chuck Schumer, according to a source close to the governor. A Senate appointee who pivots immediately to the special election would get the advantage of media attention and access to national Democratic donors.

Franken said Thursday that he would leave the Senate "in the coming weeks" after several women alleged he groped and kissed them without their consent.

Franken's office released few details Friday about his next steps, or when exactly he would leave office. A spokesman said an exact date had not been determined, and that Franken will continue to perform his duties as senator until then. Franken wants to make sure there's a smooth transition for his successor and his staff, the spokesman said.

The spokesman said Franken's office has 46 people on its payroll.

Democratic sources have told the Star Tribune that Smith is Dayton's most likely choice as a replacement. A longtime DFL insider and trusted ally to Dayton, Smith is also personally close to U.S. Sen. Amy Klobuchar, and has ties to DFL donors whose support will be vital to seriously competing in two consecutive races that could attract tens of millions of dollars in political spending.

But nothing is final until the governor makes his choice, and the high stakes around the decision have produced a swirl of rumors and speculation in Minnesota political circles.

"I won't have any comments on it until I have an announcement to make; it will be in a couple days and that's where I'm going to leave it for now," Dayton told reporters Friday after appearing at a Final Four-related event in Minneapolis.

At the same time, Dayton is facing calls from progressive activists to appoint someone other than Smith.

"As governor, you have a tremendous opportunity to make a historic appointment to fill Franken's seat," Nekima Levy-Pounds, an attorney and civil rights activist who recently ran for mayor of Minneapolis, wrote in an open letter to Dayton. "The leader who is ultimately appointed to replace Franken should not only be a woman, but she should be a woman of color."

A coalition of third-party groups — the Green, Independence, and Libertarian parties of Minnesota — called on Dayton to appoint an alternative-party candidate, rather than a DFLer, to the seat.

They also suggested he choose a woman of color.

"The appointment of a woman of color would go a long ways toward creating the change needed in Washington, D.C.," they wrote in a statement. Similar calls came from the Green Party of Minnesota's Black and Brown Caucus, the Minnesota Young DFL organization and other local leaders.

If Dayton chooses Smith, her departure would trigger a series of events at Minnesota's statehouse: a Republican state senator would be elevated into the lieutenant governor's post, at least temporarily throwing the state Senate into a 33-33 tie between DFLers and Republicans.

Under Minnesota's Constitution, a vacancy in the lieutenant governor's office must be filled by the "last presiding elected officer of the Senate." That means Smith would be replaced by Senate President Michelle Fischbach, a Republican from Paynesville who has served in the Legislature for two decades.

Her husband is Scott Fischbach, the longtime executive director of Minnesota Citizens Concerned for Life, the state's leading anti-abortion group.

Sen. Fischbach said Friday that she along with colleagues in the Legislature are combing through state statutes and century-old court cases to sort out potential political scenarios.

"It's an interesting time right now with this, because everybody's pulling out their copy of the Constitution," Fischbach said.

Fischbach said the law is clear that she's first in line to succeed Smith, should the lieutenant governor resign. Meanwhile, there's been some debate over whether the Senate president could serve in both roles at the same time. Fischbach said those suggestions are based on a late-19th century court case that considered a similar matter, but she said subsequent changes to state law make it appear unlikely.

Fischbach said she's not sure if she'd want to serve under a DFL governor — and figures Dayton's probably not thrilled either.

"We're from different parties and it's his last year [in office]," she said. "I'm sure he's taking that into consideration, too, as he looks at what to do."

At the moment, Republicans hold a one-seat majority over the DFL, with 34 seats. But DFL Sen. Dan Schoen's upcoming resignation related to sexual harassment allegations — scheduled to take effect Dec. 15 — will shift the balance to 34 Republicans and 32 DFLers.

A special election to fill Schoen's seat will be held Feb. 12, just over a week before the start of the 2018 legislative session.

Senate Majority Leader Paul Gazelka, R-Nisswa, said he and other leaders are consulting legal experts to sort out options. To maintain his party's majority and ensure a Republican keeps the Senate president's gavel, Gazelka said he's open to exploring creative options.

One idea he raised: reconvening the Legislature for a special session in which the Senate would elect a DFLer as Senate president — likely someone of Dayton's choosing — and then allow that person to become lieutenant governor. Then, the Senate would vote again to restore Fischbach as president.

"That helps both sides," Gazelka said. "We keep our majority of 34-33, and the governor gets a Democratic teammate for the last year of the term. That's the way I think it would work best."

It's unclear if Dayton is equally amenable to such a plan.

"All things are floating around," Dayton said Friday. "I'm not going to comment any more on particulars. It's all speculative."

Gazelka said he's worried that a DFL governor with a Republican lieutenant governor opens the possibility of partisan "chaos" at the Capitol.

Pressed by reporters Friday to divulge even a few more details about his thought process, Dayton resisted.

"I want someone who will be a great United States senator for Minnesota and there are a number of people who fit that bill," he said.

Star Tribune staff writer Jennifer Brooks contributed to this story.

Erin Golden • 612-673-4790