Henning Jacobson, a Lutheran pastor in Cambridge, Massachusetts, had been vaccinated against smallpox as a boy. As historian Michael Willrich writes in his terrific book, Pox: An American History, Jacobson said later that the jab brought him “great and extreme suffering.” One of his children, he said, had also suffered adverse health effects from a smallpox vaccination. He was anti-vaccine, and he thought he was right on the religious and medical aspects.

Vaccination as practiced at the end of the 19th century sometimes caused adverse reactions, or even deaths. But smallpox, a deadly and extremely contagious disease, had been scourging humanity for a millennium. Cambridge was in the grip of a smallpox outbreak in 1902. State law permitted local health boards in such a situation to require everyone to be vaccinated—with an exception for children if a doctor certified that it was too risky for them. A Board of Health doctor came to Jacobson’s door and asked him to accept a free vaccination. (Smallpox vaccinations did not confer lifelong immunity; thus Jacobson needed another dose.) He refused; a judge fined him $5—close to $150 today.

Jacobson took his case to the United States Supreme Court. He did not argue that he had special health reasons for refusing the vaccination; he argued that vaccination in general was harmful and ineffective. Some medical authorities agreed with him; most others did not. In an opinion by Justice John Marshall Harlan, the Court held, 7-2, that local governments could decide which medical authority to believe. “We are not prepared to hold that a minority … may thus defy the will of its constituted authorities, acting in good faith for all, under the legislative sanction of the state,” Harlan wrote. The government could draft some people and make them bear arms; there was no reason it could not require others to be vaccinated.

Jacobson owed the city $5.

A decade and a half later, the Court upheld a San Antonio, Texas, ordinance barring unvaccinated children from any school, public or private, where they might spread disease. The families’ constitutional challenge was not “sufficiently substantial” even to permit review, Justice Louis D. Brandeis wrote. School vaccination “ordinances confer not arbitrary power, but only that broad discretion required for the protection of the public health.”

The constitutional law of vaccination has rested there for nearly a century. Only a month ago, the U.S. Court of Appeals for the Second Circuit upheld a New York statute that permits students with “genuine and sincere” religious beliefs against vaccination to attend classes—but also permits authorities to send them home if there is an outbreak of disease. “New York law goes beyond what the Constitution requires by allowing an exemption for parents with genuine and sincere religious beliefs,” the court wrote. Thus, “the state’s more limited exclusion during an outbreak of a vaccine-preventable disease is clearly constitutional.”

In the wake of the recent measles outbreak at Disneyland, states are re-examining how broad school-vaccination exemptions should be. California currently permits parents to opt out if they have a “personal belief” of any sort, but a new bill would allow only religious objections. A legislative committee in Mississippi—a national leader in vaccination—recently refused to recommend loosening that state’s law, which permits exemptions only for children with documented medical conditions that vaccination would make worse. In the law of religious freedom, public health is clearly a “compelling” interest, and thus would allow states to refuse to exempt believers.

What’s fascinating about the current vaccination debates is how closely they mirror those of a century ago. For many anti-vaxers back then, Willrich writes, “active opposition to ‘state medicine’ … was part of a larger social and cultural struggle against the dramatic extension of governmental power into the realms of education, family life, personal belief, bodily autonomy, and speech.”

The science behind vaccination is far more compelling today than it was then, and current vaccines are far safer than the smallpox jabs that triggered riots around Europe in the 1800s. But there is now, as then, a strain of “enlightened,” alternative-medicine thought that regards vaccines as “poison,” just as Henning Jacobson did. We are also in the midst of a revival of radical libertarian ideology; fear of “state medicine” underlies a lot of the opposition to the Affordable Care Act. (Remember “creepy Uncle Sam” poking his head under the OBGYN drape, and the false claims that “death panels” would soon escort our grandparents to the death chambers?)

No society can survive if it can’t prevent epidemics and infectious disease. That’s not ideology; it’s simple history. Consider the tweeted reaction of Native American novelist Sherman Alexie to today’s controversy:

That harsh truth—that society must respond collectively to epidemics—coexists uneasily with expansive notions of individual freedom. Vaccine requires intrusion into our bodies, and the bodies of our children, for our own good and that of others. Americans find that kind of paternalism jarring, but it is inescapable. Even a libertarian giant like Richard A. Epstein recently conceded that “the Constitution’s various provisions protecting individual liberty must at times give way to government control in response to health hazards.”

The same logic, I think, would extend to a federal vaccination program, if one became necessary. In 2012, during oral argument in the challenges to the Affordable Care Act, Justice Stephen Breyer asked conservative lawyer Michael Carvin, representing small-business challengers, whether the federal government could require vaccination if a plague was certain to kill half the population. “My answer is no, they couldn’t do it,” Carvin said.

Constitutional law deals in fictions, but is there any serious argument that die-offs don’t have a “substantial effect” on foreign and interstate commerce? Isn’t there some symbolism in this year’s measles outbreak? It originated in Disneyland, an artificial world entirely created by and devoted to the national and global market.

The pandering of politicians like Chris Christie and Rand Paul strikes me as disgusting—all but disqualifying. I am a vaccine hawk. Polio disabled my grandfather for life, then hastened his death. I remember the annual summer panics over its spread, and the relief with which my parents took us to a mobile vaccination clinic. The polio-vaccination wars produced casualties—recently vaccinated children sometimes spread the virus to their parents or others—but that childhood terror is now largely gone. I had not one but two smallbox scratches; smallpox is gone now. I had measles, mumps, and chicken pox, and I am glad today’s children are spared the pain and risk. But I have also sat up all night with a fretful child after a vaccination. It was scary, and science didn’t comfort me much until morning came.

That science, however, is much clearer now than it was in 1905, or even 1985. Vaccines work; they are safer than ever; they don’t cause autism; the benefits far outweigh the risks; and we have a duty to protect ourselves, our children, and society at large. Those who deny the science are shirking a duty of citizenship. “Personal belief” in junk science won’t do; if anti-vaxers can’t be convinced, then, harsh as this sounds, they and their children need to be isolated.

It’s not retrograde, however, to argue that vaccination laws need to be carefully crafted, to be based on the best science, and to allow for medical exceptions. The power to protect the public can be a fearful one, even when wielded wisely. Justice Oliver Wendell Holmes regarded Jacobson as a proud moment for the Court. In 1927, he cited it to justify forcible sterilization of a “feeble-minded” woman named Carrie Buck. “The principle that sustains compulsory vaccination is broad enough to cover cutting the Fallopian tubes,” he wrote.