As states and companies implement vaccine mandates, some anti-vax workers have an answer: I can’t, it’s against my religion. In the past decade, battles over when religious exemptions should be granted — for various kinds of laws — have been fought in legislatures, in executive offices and in the courts. Plaintiffs have sought relief from laws prohibiting discrimination against LGBTQ couples, from requirements to cover contraceptives for employees and from pandemic-related restrictions on public gatherings.

But on the vaccine question, there is an added twist: Policymakers, employers and courts have to decide whether a person is being honest in claiming that religion is the reason they object to the vaccines. That’s because so many people are using religion as a cover for something else (such as distrust of vaccines because of something they read on the Internet).

We know that Americans game religious exemptions, because they tell us. It’s easy to find people online, for example, coaching others on how to pretend that freedom of worship is the real issue. Writes one such person, on Facebook: “RULE #4 in writing a religious exemption: Do not mention c0vid-19, side effects, or scientific data! Do not mention the V[accine] is under E-U-A,” or emergency-use authorization. Religious leaders have offered to sign letters requesting exemptions for anyone who wants one – for payment, or free. This is not a new phenomenon, nor one limited to the coronavirus vaccines. (For a hearing on vaccine mandates in Massachusetts, a parent wrote to lawmakers that she made use of a religious exemption in 2020 for the flu vaccine, “not because it goes against my religion, but because I do not believe that it is necessary to put additional chemicals into my child’s body.”) But the political battles over coronavirus vaccination have driven more people to seek ways around the laws.

Religious freedom has an important place in our Constitution and history. That said, we have always limited it to protect other important values, such as health and safety. But the line has been tricky to draw — and the Supreme Court has begun to change its mind about what the Constitution requires. All of this puts institutions trying to enforce mandates in a tough spot.

Does the law require a religious exemption to vaccine mandates? Until very recently, the answer was “no” for states and “maybe” for employers. In a landmark 1990 case, Employment Division, Department of Human Resources of Oregon v. Smith, the court ruled that states do not have to provide a religious exemption from a generally applicable law that is neutral on its face with respect to religion. Courts have consistently found that vaccine mandates do not require a religious exemption, and several states — California, Connecticut, Maine, New York, West Virginia and Mississippi — do not offer one.

But in the past year, the Supreme Court has indicated that it intends to strengthen protections for religious liberty — although the full contours of the change are unclear. In Tandon v. Newsom, for instance, it blocked California from enforcing coronavirus restrictions on private gatherings, including at-home religious services, while the U.S. Court of Appeals for the 9th Circuit considers an appeal. In Fulton v. City of Philadelphia, which gave the court a chance to overturn Smith- and to say believers should be exempt from some generally applicable laws — it declined to do so. Still, in a decision that struck some observers as hairsplitting, the court said the city had an obligation to grant an exemption from anti-discrimination laws to a Catholic adoption agency that declined to license same-sex couples to be foster parents. Justice John G. Roberts Jr., writing for the majority, noted that the law allowed exemptions at the “sole discretion” of the city’s Department of Human Services commissioner; if a city has an exemptions policy, Roberts wrote, it cannot refuse them to religious organizations without meeting a very high bar. It’s not clear yet how the recent subtle shifts in doctrine will affect court cases related to religious exemptions for vaccine mandates.

For private employers, the law is clearer: Under the Civil Rights Act of 1964, employers have to accommodate workers with religious objections to vaccine mandates — unless providing an exemption places an “undue burden” on the business in question. Private employers thus can refuse to give exemptions if the burden is too high — but should expect to be challenged in court when they do.

This murky terrain is fertile ground for lawsuits. There have been at least a dozen recently related to religious exemptions. Two University of Massachusetts students challenged the constitutionality of that system’s coronavirus vaccine mandate, with one of them also claiming that her First Amendment rights were infringed because her request for a religious exemption was denied. That case was dismissed. A Roman Catholic professor and a Buddhist student at the University of Colorado’s medical school sued to challenge the rejection of their requests for religious exemptions. The professor objected that vaccine research had been conducted on “abortion-derived cell lines”; the student said he refused “products developed through the killing or harming of animals (including human beings).” The university decided that neither objection justified a religious exemption.

Complicating matters is that most faiths do not oppose vaccines. Pope Francis has called immunization against the coronavirus “a simple yet profound way to care for one another,” for example. Mary Baker Eddy, founder of the Church of Christ, Scientist, objected to vaccines but said Christian Scientists should get them, where required. (A believer should “obey the law, and then appeal to the gospel to save him from bad physical results.”) But judges — and the people granting exemptions in the first place — are not permitted to decide what various denominations “really” teach: In court, the test is the sincerity of a personal belief that can be characterized as “religious.” There is no simple formula for gauging sincerity, but the process can involve analyzing personal statements for consistency and exploring whether people have acted over time in accordance with their stated belief. (Courts have rejected tests that evaluate the rationality of beliefs or that require letters from religious leaders, among other things.)

Faced with all of these issues, states and employers have four options. First — and worst — they can offer religious exemptions and not police them. This can avoid litigation but increase the risk of covid-19 in the workplace; the approach will literally kill people. It’s also ethically dubious: Using faith as a fig leaf is not something society should encourage (nor would most religious leaders support it). Widespread abuse would also lead to eventual scrutiny — and tightening scrutiny can hurt the very few people who truly oppose vaccination for religious reasons.

Second, states and employers can choose not to provide religious exemptions and accept that they can be sued over it. Until the Supreme Court speaks, courts will go different ways. A district court in New York this past week required the state to give an exemption to health-care workers on such grounds, while their challenge to the mandate makes its way through the courts — but two other New York courts, examining exactly the same facts, did not. Since employers and states can still be sued if they offer exemptions but refuse some petitioners, it may be worth standing their ground and arguing that the harms and deaths caused by exemptions are simply too high a price to pay — an “undue burden.”

Third, these entities can offer religious exemptions and police them. Some employers have been doing this in creative ways, including by asking detailed questions. The Conway Regional Health System in Arkansas, for example, requires that people who claim to oppose vaccines because of their use of cell lines from decades-old abortions also attest that they do not use other products that were tested on cell lines, a long list that includes Tylenol, aspirin and Benadryl.

Finally, employers can offer an open “personal” exemption, not limited to religion — thereby avoiding the challenge of deciding what counts as a religious view — but attach significant strings to it. For example, a company might require that people who seek exemptions take a course that includes information on the safety of various vaccines, as revealed by clinical trials. Or an employer might require routine and frequent testing and prohibit business travel to places that require vaccines. (It’s possible the businesses might be challenged on the grounds that this is not a true exemption.)

Granting religious exemptions will always be an inexact science. But employers and states should still do their best to guard against outright deceit: After all, religious citizens will be among the first to agree that you should not take the Lord’s name in vain.

Dorit Reiss is a professor of law and the James Edgar Hervey ’50 chair of litigation at the University of California Hastings College of Law.