Political operatives in Minnesota and Washington were drawing up lists of candidates to run for Sen. Al Franken's Senate seat even before his resignation speech last week, searching for prospects with the profile, fundraising prowess and mettle to sprint to next November's special election — and then do it again in 2020 to hold the seat another six years.

Franken's decision to step down amid a growing sexual-harassment scandal has scrambled Minnesota's 2018 election, which was already on track to be the most high-stakes political cycle in the state in years. The looming battle for control of the U.S. House could run through up to five competitive races in Minnesota, and an open governor's race puts Republicans in a position to take full control of state government for the first time in half a century.

No one has declared for the new Senate race yet, but many big names are in the mix. DFL Lt. Gov. Tina Smith and former Republican Gov. Tim Pawlenty are among those being discussed, but both parties will consider a half dozen or more possible contenders. Smith, seen as Gov. Mark Dayton's likeliest choice as Franken's immediate replacement through the special election, has emerged as a possible candidate for the long term. She was initially viewed as a caretaker appointment who wouldn't run.

"Anyone who gets in will need to demonstrate an ability to organize quickly, fundraise and create a campaign to go the distance, and the distance is 2018 and then again in 2020. That will be a deterrent," said Doug Loon, president of the Minnesota Chamber of Commerce. Spending on contested U.S. Senate races easily reaches into the tens of millions of dollars, and candidates face a level of scrutiny that's probably second only to presidential contenders.

The Senate race also promises to change the political landscape in Minnesota.

Republicans say fears about losing ground in the first midterm election under a new president of the same party — disastrous for the president's party in 1982, 1994 and 2010 — are alleviated in a special election.

"The conventional wisdom is that voters on the left are motivated and the Trump midterm will be problematic for us, but I think this Franken resignation scrambles that, and I think you'll see Republicans eager to get out and vote in 2018," said Brian McClung, former deputy chief of staff to Pawlenty and now a partner in a public affairs firm.

Republicans say the race to replace Franken will take on special meaning for many Minnesota Republicans, who are motivated by lingering memories of how narrowly they lost in 2008, when 312 votes decided the issue after a recount and court battle.

"A lot of Republicans — myself included — believe we held the seat in 2008 and lost it in a court battle, so this is an opportunity to get it back," said Carl Kuhle, a GOP operative with ties to U.S. Rep. Tom Emmer, whose name has also been mentioned as a potential candidate.

Democrats were still stunned at the end of the week by the rapid series of events that have made the special election necessary, having suddenly lost in Franken a marquee politician who had been widely revered by party activists. But party operatives and allies also see a high-profile race that could help with one of their ongoing challenges: turning out their base in midterm elections, when they traditionally lose hundreds of thousands of voters to apathy. The turnout in 2014 was 50 percent, compared to 76 percent in 2012 — a difference of nearly 1 million votes, with punishing effects for the DFL.

"Turnout is always a problem in a midterm elections," said Bill McCarthy, president of the Minnesota AFL-CIO.

Joe Davis, the executive director of the DFL-aligned Alliance for a Better Minnesota, said a second Senate race will further nationalize the Minnesota election, which can only help the DFL chain Republican candidates to a historically unpopular president. "It's a chance to put not just one but two checks on Trump's Washington," Davis said, referring to the special election as well as DFL Sen. Amy Klobuchar's re-election. DFLers hope that anti-Trump fervor will trickle down the ballot to the governor's race and legislative contests.

Franken's absence will also allow DFL candidates to run unencumbered with constant questions about whether they think Franken should resign over allegations of inappropriate behavior toward women.

"In holding candidates and elected officials to a high standard, there's now a clear choice for people who might otherwise say the two parties are all the same," Davis said. "In order to be different in voters' minds, we have to act different."

Each side is deep in deliberations about the right candidate, and activists and operatives in both parties are especially focused on women, given the nature of Franken's departure.

"It should be a woman. I feel even stronger about that than I have in the governor's race," said Brian McDaniel, a Republican lobbyist.

State Sen. Karin Housley, R-St. Mary's Point, said she is mulling the race and will make a decision early this week. Sen. Julie Rosen, R-Vernon Center, said she remains focused on a potential run for governor and has no interest in the U.S. Senate. State Sen. Michelle Benson, R-Ham Lake, said she is talking it over with family this weekend.

The Republican dilemma mirrors the challenge they've faced in the governor's race: The party has been successful at the Legislature but has not won a statewide election in more than a decade.

Enter Pawlenty: "From a national Republican point of view, he's a dream candidate," said Josh Holmes, a Minnesotan who is former chief of staff to Senate Majority Leader Mitch McConnell and now a D.C. consultant. "He's well regarded, won statewide elections and has the capability of doing the job."

Pawlenty is now a banking lobbyist who shuttles between D.C. and Minnesota. The Financial Services Roundtable paid him $2.6 million in 2015, according to IRS documents. His lobbying work gives him access to the $15 million to $20 million that political operatives say would be needed in each of the 2018 and 2020 elections.

But it also carries the odor of insiderism that voters are rebelling against in recent elections. Alliance for a Better Minnesota commissioned a poll from Public Policy Polling in November: Of the 871 Minnesota voters interviewed, 33 percent said they have a favorable opinion of Pawlenty, while 36 percent have an unfavorable opinion.

Other Republicans who could be considered viable include U.S. Reps Jason Lewis and Erik Paulsen, state Senate Majority Leader Paul Gazelka and House Speaker Kurt Daudt, among others.

The DFL has a deep reserve of elected officials to draw upon. Attorney General Lori Swanson would offer the most statewide experience, though until now she had been expected to announce a run for governor.

Both U.S. Reps. Keith Ellison and Betty McCollum have a strong base in the Twin Cities, but their statewide appeal is untested. U.S. Rep. Rick Nolan offers support in the Eighth Congressional District in northeastern Minnesota but is less well known in the Twin Cities.

Former President Barack Obama's longest-serving chief of staff, Denis McDonough, comes from a prominent Stillwater family and would be able to tap into Obama's vast political and fundraising network.

McCarthy, the president of the AFL-CIO, said he encouraged Dayton to appoint the best DFL candidate for 2018 to confer the advantages of incumbency going into 2018 and 2020. McCarthy's voice was filled with trepidation as he mulled the prospect of another expensive battle for the labor movement: "It's one more race we have to be concerned about."

J. Patrick Coolican • 651-925-5042