SIOUX FALLS, S.D. — South Dakota’s House speaker plans to put two ballot measures before voters that would ban out-of-state political contributions for ballot questions and raise tobacco taxes to improve tech school affordability, an unorthodox move by a high-ranking lawmaker well-positioned to sway state policy.

But Mark Mickelson, a member of a famous South Dakota political family, has proven unpredictable since joining the Legislature in 2013. The Sioux Falls Republican said he’s taking the measures to the voters because it’s unlikely they would prevail in the statehouse.

A similar contribution cap bill failed this year, and the Republican-held chambers are unlikely to support a tobacco tax increase, said Mickelson, who has been a booster for South Dakota’s four technical institutes. The 51-year-old businessman said he concluded that the ideas would attract public support even if he couldn’t get fellow lawmakers to pass them.

Mickelson formed a ballot question committee this week for the out-of-state donation ban and said he hopes to start gathering signatures for both measures in August.

These will be the inaugural initiative campaigns for a lawmaker colleagues describe as a tenacious political tactician. But they don’t mark the first time Mickelson has eyed a statewide race — he had started following his father and grandfather to the governor’s office before a surprise decision last year not to run because he didn’t enjoy it enough. He returned more than $860,000 in contributions in the end.

“There’s no personal gain,” Mickelson said in an interview about the ballot measures. “I’m not seeking a higher political office. I thought I wanted to, and I don’t. I’m only doing these for one reason: I believe in them, and I think they’ll make a difference, and that’s rewarding work.”

Mickelson said the 2016 campaign attracted more than $10 million in out-of-state money for ballot measures, most of which were brought by people using South Dakota as a testing ground for their ideas. His initiative would prohibit contributions to ballot question committees from nonresidents, out-of-state political committees and entities that haven’t filed with the Secretary of State’s office for the preceding four years.

Experts have said such measures are unlikely to survive a legal challenge, and critics argue they would restrict free speech.

The tobacco tax plan aims to make state technical institutes more affordable and raise money to offer more programming, and Mickelson said lowering the cost of attendance would help keep young people in South Dakota.

Republican Sen. Stace Nelson, a well-known conservative, asked state residents to reject both initiatives, saying he opposes Mickelson’s “tax and spend ideas” and encouraging him to change his party registration to Democrat.

Gov. Dennis Daugaard’s chief of staff, Tony Venhuizen, said that Mickelson is an “aggressive” guy who ran for office to get things done. During the 2017 session, the speaker hired his own private lobbyist, an unusual move for South Dakota’s part-time, citizen Legislature.

Senate President Pro Tempore Brock Greenfield said Mickelson has seemed freer since deciding not to join the Republican gubernatorial primary because he doesn’t have to worry about the campaign. Though he criticized the tax hike plan, Greenfield praised Mickelson’s strategic ability.

“He’s certainly determined,” Greenfield said. “He’s a man of means and a man with a good network, and it appears that he’s going to utilize his resources in order to try to get something done at the ballot box. I’ve never even considered doing something like that.”