Vaccine mandates have arrived. And so, too, has opposition led by Republicans. Nineteen Republican governors spoke out against President Biden’s announcement Thursday that American workers in large businesses must be vaccinated or face weekly testing. A half-dozen GOP governors threatened to sue, alongside the Republican National Committee.

But the legal ground they have to stand on appears rather shaky, based on a century of Supreme Court precedent.

The crux of the debate is where one’s personal freedom lies in relation to the broader health and rights of the nation.

About a century ago, in 1905, the Supreme Court was asked a similar question and sided with the vaccine mandates.

In 1905, at the height of a smallpox outbreak and at a time when infectious diseases were the No. 1 killer in America, the court considered whether Cambridge, Mass., could force people to get vaccinated for it. There was intense and passionate resistance to these vaccine mandates, with some people going so far as to burn their arm with nitric acid to make it look like they had smallpox, which left a scar, the New York Times reports.

A local pastor, Henning Jacobson, resisted, claiming and his son had bad reactions to earlier vaccines. He sued Cambridge and argued that “compulsion to introduce disease into a healthy system is a violation of liberty” and that being forced to take the vaccine violated his 14th Amendment rights, which says that no state shall “deprive any person of life, liberty, or property.”

That was a relatively easy no for the court. In a 7-to-2 ruling in Jacobson v. Massachusetts, it decided that jurisdictions do have the right to require people to get vaccinated. Back then, the government was much more forceful about it, knocking down people’s doors to get them vaccinated, the New York Times says.

Justice John Marshall Harlan wrote, rather presciently for today’s pandemic, that: “upon the principle of self-defense, of paramount necessity, a community has the right to protect itself against an epidemic of disease which threatens the safety of its members.”

He hit at this core idea among vaccine-mandate skeptics that personal liberty must come above all else. Liberty, he wrote, is not “an absolute right in each person to be, in all times, and in all circumstances, wholly freed from restraint.”

But even as the justices expounded on where the lines of civil liberty are drawn, they didn’t make broad or sweeping determinations about vaccine mandates. It was specific to this Cambridge case.

President Biden expressed his disappointment in some Republican governors ‘cavalier attitudes’ towards school coronavirus safety measures on Sept. 10. (The Washington Post)

An anti-vaccination league (not just anti-vaccine mandate) got started up a few years after that, writes Nicholas Mosvick at the National Constitution Center. And over the years, the Jacobson case got rechallenged and re-upheld. The Supreme Court has generally leaned to the side of giving the government authority to protect public health.

“Laws that restrict … liberty rights need only be ‘rationally related’ to any ‘legitimate state interest,’ and the Court continues to accept almost any plausible reason as justification,” three scholars with the state of Massachusetts wrote in 2005, summarizing the court’s various other rulings on this.

The American Civil Liberties Union recently raised another Supreme Court case for people who say they won’t get vaccinated on religious grounds: The 1944 case Prince v. Massachusetts, where the court decided a Jehovah’s Witness could continue to employ her child on the street to sell literature.

But the justices put boundaries on religious freedom, writing: “The right to practice religion freely does not include liberty to expose the community or the child to communicable disease or the latter to ill health or death.’”

Today, arguably more modern laws and institutions apply to vaccine mandates. The Labor Department’s Occupational Safety and Health Administration handles workplace safety, and it has the legal authority to mandate vaccines to keep workers safe, says Barbara McQuade, a former U.S. attorney in the Obama and Trump administrations now at University of Michigan Law School. “OSHA’s mission is to ensure safe and healthy working conditions by setting and enforcing workplace standards for private employers,” she said.

That’s not to say what Biden is mandating is completely normal. A former OSHA official under the Obama administration said to my colleagues at The Washington Post that the agency decided against mandating a hepatitis B vaccine for workers who regularly come into contact with blood.

The Biden administration is also offering an out to vaccine skeptics: Face weekly testing if you don’t want to get vaccinated. McQuade said she thinks the administration has the authority to mandate vaccines, period. The testing alternative, she said, “strikes me as a way to make the initiative more politically palatable.”

It’s a fair policy question of whether, in a capitalist society, businesses should be free to make their own decisions that pertain to the health of their employees and customers. “That’s really a free-enterprise decision that should be made by companies, and not the government,” Rick Murray, chairman of the government affairs committee at the Arizona Small Business Association, told my colleagues at The Post.

But now that the government has decided it’s time to force workers to get vaccinated, there doesn’t seem to be much legal ground skeptics have to stand on to say no.