Sure enough, a number of companies are already snubbing Abbott’s directive. Most notably, American Airlines and Southwest Airlines, both of which already require employees to be vaccinated, released statements last week saying the governor’s order won’t change their policies. 

Vaccine mandates are legal

There’s a long precedent for vaccine mandates in the U.S. The first dates back all the way to 1809, when Massachusetts required inoculation against smallpox. Then, in 1905, the Supreme Court affirmed in Jacobson v. Massachusetts that state and local governments could mandate vaccines for nearly every resident. The court again upheld that precedent in 1922, this time ruling in favor of mandates in schools.

Both those cases centered on a state’s ability to mandate vaccines, not the federal government’s. That’s why Biden’s mandate doesn’t require all citizens to get vaccinated and instead targets specific groups of people, like government employees and anyone who works at a facility that receives federal Medicaid or Medicare funding.

When it comes to the employer mandate, it falls to the Labor Department’s Occupational Safety and Health Administration (OSHA) to create the rule requiring shots. “President Biden can’t go out and say, ‘Businesses require vaccines,’” unless there is a law that authorizes his agencies to require vaccines. In this case, his claim is that the Occupational Safety and Health Act has that right,” said University of Montana law professor Anthony Johnstone.

On Oct. 12, OSHA submitted the text for that regulation to the Office of Management and Budget (OMB); once OMB reviews the rule, it will be published in the Federal Register—that is, the government’s official journal—at which point it will go into effect. Per OSHA’s rule, large businesses will have to give their employees paid time off to get vaccinated; any employer that doesn’t comply could face a fine of up to $14,000 per violation.

Assuming OSHA’s rule gets OMB’s stamp of approval, there is still likely to be a flurry of lawsuits against the mandate. “There will certainly be litigation over the validity of an OSHA vaccine mandate,” said Andrew Coan, a law professor and director of the William H. Rehnquist Center on the Constitutional Structures of Government at the University of Arizona. “And these challenges will probably get a sympathetic hearing before at least some federal judges.”

Yet it’s highly unlikely a judge would rule against OSHA’s policy—or that they would rule in favor of a state-level ban. “No state can prohibit private citizens or businesses from complying with a valid federal regulation,” said Coan.

Why mandate bans have little hope of success

Though their ordinances vary, at least eight states—Arkansas, Georgia, Indiana, Utah, Tennessee, Texas, Michigan, and Montana—have banned state or local agencies from mandating vaccines. (In addition, Florida Gov. Ron DeSantis signed a bill in May prohibiting vaccine “passports.”) Of these eight states, only Texas and Montana have extended the mandate ban to private employers; most of the others’ bans extend to government workers. And whereas Texas’s ban arrived via executive order, Montana’s came through legislation. 

But regardless of whatever legal gymnastics state legislators pull to come up with their ban, it’s all for naught assuming Biden’s executive order is implemented via OSHA. “If the federal vaccine mandate policies are valid under federal law, then they are the supreme law of the land, and no state policy to the contrary would be effective,” said University of Montana’s Johnstone.

Further hurting any sort of anti-mandate case is the Constitution’s Commerce Clause, which essentially allows Congress to regulate conduct that involves interstate commerce. “The Commerce Clause basically says states have a lot of authority to regulate health, safety, people’s welfare, those kinds of things. But there may be times when states do things that simply impose too many costs on other states, or they are passing laws [where] the spillover effects on businesses and economic interests in other states are simply too great,” explained Sanders, the Indiana University professor. 

So why would states like Texas and Montana go through all this trouble in the first place? “I tend to think this is more politically motivated,” said Srividhya Ragavan, a professor at Texas A&M University School of Law who specializes in public health.

Ragavan noted that, in a world that’s been hobbled by the pandemic, these bans could set us back in the fight against COVID. “Until the globe is fully vaccinated and poorer countries are able to get back on their feet, we‘re never going to get back to the objective of global trade doing well,” she said. “From that perspective, we really have to resolve these issues.”

Correction, Oct. 20, 2021: A previous version of this article misidentified Steve Sanders’ employer. He is a constitutional law professor at Indiana University.