The anti-vaxxer disease is now a Republican epidemic.

What was once the provenance of a few fringe weirdos—mostly on the loony left—has now migrated into the mainstream. At least three Republican candidates for governor—in Oklahoma, Oregon, and Connecticut—are now open skeptics of requiring vaccinations for school kids.

In Connecticut, Bob Stefanowski, currently trailing his Democratic opponent, told a Tea Party group last summer that whether children should be required to be vaccinated in order to attend public school “depends on the vaccination.”

“We shouldn’t be dumping a lot of drugs into kids for no reason,” he added.

Asked to explain that remark, a Stefanowski aide said that “while [Stefanowski] believes that the best practice is to vaccinate your children, he does not believe that the government should be able to legally force you to do so.”

In Oregon, Dr. Knute Buehler—yes, a physician—said that “parents should have the right to opt out” of vaccinations “for personal beliefs, for religious beliefs or even if they have strong alternative medical beliefs.”

Buehler described the opt-out system as beneficial. “I think that gives people option and choice and that’s the policy I would continue to pursue as Oregon’s governor,” he said.

And in Oklahoma, Kevin Stitt, the favorite in the governor’s race, said in February that “I believe in choice. And we’ve got six children and we don’t vaccinate, we don’t do vaccinations on all of our children. So we definitely pick and choose which ones we’re gonna do. It’s gotta be up to the parents, we can never mandate that. I think there’s legislation right now that are trying to mandate that to go to public schools, it’s absolutely wrong. My wife was home schooled, I went to public schools, our kids go to Christian school, and that’s back to a parent’s choice.”

This is no harmless, Gwyneth-Paltrow-style pseudoscience. Anti-vaxxer nonsense poses an existential risk to thousands of people on the basis of rumor, ignorance, and fear.

First, to be absolutely clear, there is no link whatsoever between the MMR vaccine and autism. Vaccinations are safe. Multiple vaccines at once are safe. Autism rates are not rising.

Second, vaccination is not a matter of personal choice. Since some people cannot be vaccinated for medical reasons, they are vulnerable to preventable diseases like measles. Having non-vaccinated kids in their homeroom, because the kids’ parents believe in fairy tales rather than science, can cause them to get sick and even die.

That’s also true for babies who haven’t been vaccinated yet. The children of some ignorant anti-vaxxer could be carrying measles and then infect an infant without anyone knowing it.

Worst of all, thanks to the effect known as herd immunity, once a group’s overall vaccination level drops below a certain threshold (for measles, the threshold is around 94 percent), it makes it virtually impossible to contain the spread of disease. Too many unvaccinated people, and the disease has too many opportunities to travel throughout a population.

In other words, vaccination is a public health issue, not a private one.

So how did this happen? Part of it is ideology. Republicans don’t like government forcing people to do stuff, and requiring children to be vaccinated in order to attend public school runs afoul of that libertarian impulse. (Notably, Kentucky Sen. Rand Paul was one of the first nationally known Republicans to propose making vaccination non-mandatory.)

Part of it is the magnifying effect of social media, which flattens the difference between truth and lies.

Part of it, as a Daily Beast study showed in 2016, is Donald Trump personally. More than any other politician, Trump normalized anti-vaxx mythology, expressing doubts about the efficacy of vaccines and concerns about their (non-existent) link to autism. As measured in July, 2016, 23 percent of the respondents who said they would vote Trump said they were unlikely to get vaccinated. Of the pro-Clinton respondents, 13.5 percent felt the same way.

And part of it, surely, is the anti-science bias of the current administration. Sure, not a single peer-reviewed study has linked vaccination to autism. Sure, the entire myth, as is now known, derives from a single, wholly debunked bit of pseudoscience by Andrew Wakefield—a report discredited, withdrawn, refuted, and disavowed.

“ The vaccine issue is a canary in the coal mine of American civil society. If we can’t come together on protecting kids from getting measles, we really are coming apart at the seams. ”

But who knows anything anyway? Seventy-three percent of Republicans think climate change isn’t a thing. Fifty-seven percent of Republicans think evolution isn’t a thing. And now the Trump administration wants to say that transgender isn’t a thing either. This despite the near-unanimous scientific consensus that all three are, indeed, things. The lack of causal connections between vaccines and neurological disorders are just the latest bit of reality denial.

The problem is, these three Republican candidates for governor, like all anti-vaxxers, are dead wrong, and their policies could lead to very sick and even dead schoolchildren.

And, let’s remember, the laws these quasi-libertarians are concerned about only govern public schools. Underscore public. If you really, truly believe that vaccinations are bad for you, or fluoridated water is a government plot, or whatever, keep your kids in private school that don’t require vaccinations or home-school. At least that way you’re only putting other people’s babies and vulnerable children at risk at playgrounds, restaurants, buses, and museums. Schools, at least, are safe.

Whatever its causes, the mainstreaming of anti-vaxx paranoia is a profound moral crisis for conservatives.

First, the silence of conservative leaders, especially religious leaders, is more than just the latest instance of moral cowardice in the face of political expediency. It’s a betrayal of one of the religious right’s supposedly central commitments: protecting the lives of the innocent. It represents the triumph of reflexive anti-government thinking over deeply held moral principles.(Never mind that the anti-vaxx myth initially sprung up on the left, not the right.)

Second, there appears to be no limit to the conservatives’ denial of the scientific method, rational truth, and objective reality. It’s one thing to deny climate change (there’s a whole industry that depends on that) or the realities of gender and sexual orientation—the truths about our bodies and minds run afoul of conservative Christian dogma about how the world supposedly is.

But public health? Since when did that become politicized? Is there any consensual reality that today’s Republican Party won’t deny? Is there any wacko conspiracy that Republican leaders won’t believe? What’s next: flat-earthers? I was joking earlier about fluoride in the water, but guess what, that particular conspiracy theory is making a comeback.

The vaccine issue is a canary in the coal mine of American civil society. If we can’t come together on protecting kids from getting measles, we really are coming apart at the seams.

Just a few years ago, the anti-vaxxer “movement” was a small fringe group of weirdos. At first, they were just ludicrous. Then, when the first kids started getting measles, they were dangerous wingnuts. Now, they are running for governor as the Republican nominees in at least three states. At least one is likely to win.

God help us.