WATERTOWN — The small-town family doctor angling to become Minnesota’s next governor smiled, leaned into the camera and told his Facebook viewers that Sweden had just paused the Moderna vaccine for people under age 30 over “significant concern” about heart inflammation.

Dr. Scott Jensen, clad in a white lab coat, quickly pivoted: “So what happens to military people who are threatened with a dishonorable discharge if they are unwilling to potentially put their heart health at risk?”

The post swiftly racked up thousands of views and favorable comments — evidence of Jensen’s early success in tapping conservative anger at the Democratic strategy of trying to vaccinate, mask and social-distance America out of the COVID-19 pandemic.

Messages like the video have been a key part of how Jensen, a former state senator with a reputation as a moderate before the pandemic hit, has emerged as the early frontrunner among Republicans seeking to unseat Democratic Gov. Tim Walz.

Jensen’s video drew a cautionary label from Facebook attesting to the safety of vaccines. Earlier this year, he had been temporarily banned from advertising on the site and was kicked off TikTok for allegedly spreading misinformation, though the social media platforms never said exactly why.

The Minnesota Board of Medical Practice has opened — and dropped — four investigations against Jensen, based on anonymous allegations that he spread misinformation and gave bad advice about COVID-19. Jensen has discussed the cases on social media but declined to release the letters he received from the board, whose investigations are not public unless they result in disciplinary action.

Jensen has not been vaccinated against the coronavirus, although he says he would “absolutely” get vaccinated against the coronavirus if he didn’t already have antibodies from a mild case. (The Centers for Disease Control advises vaccinations even for people who have already had the virus.)

Sen. Matt Klein, a Democrat and fellow doctor who got to know Jensen in the Legislature, said he’s astonished at what he’s heard from Jensen during the pandemic.

“I’m seeing patients that are actively being harmed or dying from sort of misinformation that he is propagating,” Klein said.

Jensen, 66, often deviated from Republican orthodoxy during a single term in the Minnesota Senate that ended last year.

He was willing to at least consider gun control legislation, such as universal background checks, and legalizing recreational marijuana. He brokered a compromise to end a bitter partisan stalemate over insulin prices. He took on industry by winning enactment of a law to regulate pharmacy benefit managers.

As the pandemic took hold, he began questioning the federal government’s methodology for determining when the disease should be listed as cause of death. That launched him on a path of frequent appearances on Fox News and other conservative media. In May, he was briefly a plaintiff in a lawsuit seeking to block vaccines for 12- to 15-year-olds that was filed by America’s Frontline Doctors, led by Simone Gold, who was arrested during the Jan. 6 insurrection at the U.S. Capitol. More recently, he called for “civil disobedience” and legislation to ban vaccine mandates by employers.

His busy schedule of campaign appearances across the state included a slot last month as a featured speaker at a “Global Health Freedom Summit” in western Minnesota. There, he joined a panel discussion with some of the bigger names in the anti-vax world, including some who have pushed the falsehood that coronavirus vaccines contain microchips that the government might use to track people.

Among the thousands who viewed his video on the Sweden vaccine news was Sheila Decker of Moorhead, Minnesota, who had met him earlier at the health freedom event.

“He’s like a breath of fresh air to me,” Decker said in an interview. “He’s honest, he’s trustworthy.” She said she supports Jensen because she opposes vaccine and mask mandates and she doesn’t like how Walz handled the pandemic, including his orders to close restaurants and businesses.

At Jensen’s clinic in Watertown, where the western Minneapolis suburbs give way to farm country, there are no signs requiring or even encouraging patients to wear masks. The exam rooms reflect his individuality. One is decorated like a North Woods cabin, with log furniture, a potbellied stove and a walleye on the wall. Another has mementos of the “M(asterisk)A(asterisk)S(asterisk)H” TV series, complete with a fake IV bottle on the wall labeled “vodka.”

Klein, who has treated many seriously ill COVID-19 patients at Hennepin County Medical Center and the Mayo Clinic — and seen many die — said he was impressed with Jensen’s medical skills when they both rushed to Gov. Mark Dayton’s aid when Dayton collapsed during a speech in 2017. He said he considered Jensen “a competent and a fairly conscientious physician” before the pandemic.

But Klein said the positions Jensen is advocating now are “anti-science and radical.” He said Jensen must know that masks work, that the vast majority of hospitalized COVID-19 patients are unvaccinated, and that immunity gained from being infected with the coronavirus isn’t as strong as from a vaccination.

In an interview with The Associated Press, Jensen acknowledged being a “contrarian” but said he’s not anti-vaccine or anti-science, a charge frequently leveled by Democrats.

“I don’t see myself as being hyper-conservative on COVID,” he said. “I see myself as being an outspoken skeptic.”

Jensen’s messaging sets him apart from his two best-known Republican rivals, former Senate Majority Leader Paul Gazelka and Sen. Michelle Benson. Gazelka and Benson have also attacked Walz’s handling of the pandemic and promoted personal choice on vaccines but haven’t gone nearly as far as Jensen in challenging the conventional scientific wisdom.

State Democratic Party Chairman Ken Martin said Jensen draws support from followers of former President Donald Trump who enjoy “raging against the machine” — a recipe Martin said could win a primary weighted toward base voters but lose a general election that requires moderates to win.

Jensen says he’d like to move beyond a singular focus on COVID-19 and talk more about public safety, education and the economy.

“I can’t tell you how many times I would talk to my team and I say, ‘We have got to move away from COVID. We have got to start talking more about what can we do to make people’s lives better.’ … But it seems like COVID, or something COVID, always seems to raise its head and pull us back.”