It’s been a little more than four years since the anti-vaccine movement suddenly seemed to be gaining a foothold in American government. Donald Trump, who had long espoused debunked theories linking vaccines to autism, won the presidency. And shortly before his inauguration, prominent vaccine skeptic Robert F. Kennedy Jr. said Trump had tasked him with heading up a new commission on vaccine safety.

The Trump transition team quickly disputed Kennedy’s claim, and the whole thing never got off the ground.

But four years later, it has become clear how Trump’s elevation of such fringe figures and theories has caught on — particularly when it comes to state legislatures debating coronavirus vaccines.

On several occasions in recent months, state legislators have invited witnesses with histories of vaccine-related and other conspiracy theories to testify in front of their supposedly august committees.

The most recent involves an Ohio doctor, Sherri Tenpenny, who has said she wears the title of “anti-vaxx” proudly and has falsely suggested the coronavirus vaccine is a deadly bioweapon. In her testimony, video of which has gone viral, she floated a false theory that the coronavirus vaccines might cause people to become “magnetized.”

“I’m sure you’ve seen the pictures all over the Internet of people who have had these shots and now they’re magnetized,” Tenpenny said. “They can put a key on their forehead. It sticks. They can put spoons and forks all over them and they can stick, because now we think that there’s a metal piece to that.”

As The Post’s Andrea Salcedo reports, Tenpenny also suggested vaccines “interface” with 5G cellular towers — a more well-trafficked but also false claim. But she received little pushback from the legislators present.

The thing about Tenpenny is that, if you watch the video above, she doesn’t come across as a quack. Setting aside the content of her claims, she presents as an entirely reasonable and studied person (which makes inviting to spout these claims more dangerous).

That’s a marked contrast to the last state legislative witness to go viral for her outlandish claims, Mellissa Carone. In December, Carone lodged various conspiracy theories about voter fraud in a hearing in Michigan, to the point where even Trump’s lawyer Rudolph W. Giuliani, who was seated next to her, sought to rein her in. Unlike Tenpenny, though, Carone didn’t exactly play the part of a sober-minded witness; her presentation and interactions with lawmakers were so bizarre that they were lampooned on “Saturday Night Live” (which, honestly, didn’t even need to embellish much).

In the six months between those two viral moments, though, we’ve seen plenty of other fringe figures elevated to testify to reflect conservative concerns about coronavirus vaccines and related issues.

In the days after Carone’s testimony, U.S. Senate Republicans invited vaccine skeptic Jane M. Orient to testify in front of the Senate Homeland Security Committee, drawing criticism from Democrats. Orient’s views are less extreme than Tenpenny’s, but she belongs to a group, the Association of American Physicians and Surgeons (AAPS), that has elevated extreme rhetoric, as The Post reported in 2017:

Orient is the editor of an AAPS quarterly journal. Its articles, which she said are peer-reviewed, do not necessarily reflect the group’s positions. Over the years, some have asserted that the “gay male lifestyle” shortens life expectancy and that disabled babies of undocumented immigrants are “valuable” for generating welfare benefits for their families. In spring 2015, one contended that the research establishing that HIV causes AIDS “is proving to be a substantial fallacy of modern medicine.”

In February, Ohio — the same state in which Tenpenny testified — featured testimony from anti-lockdown activist Thomas Renz, who used that platform to falsely assert that no children in Ohio had died from the coronavirus, among other claims. Video of his testimony was later removed by YouTube, citing its policy against coronavirus misinformation.

Michigan, too, has repeat experience with this. Last month, the state legislature invited Naomi Wolf, whose coronavirus conspiracy theories are numerous and routinely bizarre, and ultimately got her suspended from Twitter last week. In January, it invited testimony from Jayme McElvany, whom the Associated Press described as “a virus skeptic who also has posted about the QAnon conspiracy and former president Donald Trump’s unfounded claims of election fraud.”

Louisiana also featured testimony about vaccines a few weeks ago from Martha Huckabay, the leader of a New Orleans-based women’s group. In the weeks prior to her testimony, Huckabay drew a backlash for citing some of the supposedly undersold, good aspects of slavery. The comment led some Republicans to disown her as a gadfly and one conservative radio and TV host to disinvite her as a panelist. Huckabay has also spouted various conspiracy theories about vaccines.

Despite all of that, Huckabay was deemed to be someone worthy of testifying to the Louisiana House Committee on Civil Law and Procedure, during which she claimed to have been infected with the coronavirus twice.

Many of these witnesses have testified narrowly about valid legal issues like whether people should be required to get the vaccines in one context or another. But the fact that they are the ones leading the charge — and that lawmakers have seen fit to invite them to do so — would seem to say plenty about who is truly leading that effort in the conservative movement these days.

Tenpenny might be the most pronounced example of inviting such people going awry, but almost all of these witnesses’ views on various issues were easily obtainable via a brief Google search.

There was a time in which such conspiracy theories were something that political parties would strain hard to avoid virtually any association with. That time seems to have passed us by. Those who spout debunked theories about things like voter fraud, QAnon and even coronavirus vaccines that are rescuing us from a deadly pandemic are now regarded as people worth hearing from.