The Supreme Court heard arguments on Wednesday in a case that poses a bizarre question: Once states provide public funds to private schools, are they obligated to fund parochial schools, too? The answer should be obvious: Of course the Constitution does not require states to subsidize religious education—to the contrary, it limits the government’s ability to finance religion. Yet the court’s conservative majority may be prepared to turn the First Amendment on its head, compelling states to underwrite the religious indoctrination of children.

Wednesday’s case, Espinoza v. Montana Department of Revenue, demonstrates just how far the Supreme Court has shifted to the right in recent years. SCOTUS did not uphold vouchers for parochial schools until 2002’s Zelman v. Simmons-Harris, a 5–4 decision that drew sharp dissents from the liberal justices. Zelman opened the door to “indirect funding” for religious education, which proliferated in its wake.

Today, 29 states, the District of Columbia, and Puerto Rico provide either vouchers or tax credits that reimburse parents who send their children to private schools. Montana is one of those states, but it might not be for much longer. In 2015, the legislature enacted a program that gave a tax credit of up to $150 to individuals who donate to scholarship organizations. These groups then use the donations to award scholarships to students who attend private schools, including religious ones. But the Montana constitution bars the state from using public funds to aid any school that is “controlled in whole or in part by any church, sect, or denomination.” In light of this provision, the Montana Supreme Court ruled the tax credit scheme unlawful in 2018. Rather than limit state funding to secular schools, the court invalidated the entire program.

The plaintiffs in Espinoza, who are represented by the libertarian Institute for Justice, are parents who wanted scholarships to keep their children at a Christian school. They allege that the Montana Supreme Court violated the First Amendment’s free exercise clause by axing the scheme. But the plaintiffs have a problem. The core of their argument is that once states fund private schools, they have to include religious schools. Montana, however, can no longer fund any private schools, secular or sectarian. So, the plaintiffs make the broader claim that states cannot stop funding all private schools to avoid giving money to religious ones.

During arguments on Wednesday, the liberal justices were skeptical of all this. Because of the Montana Supreme Court’s decision, Justice Elena Kagan told the Institute for Justice’s Richard Komer, “whether you go to a religious school or you go to a secular private school, you’re in the same boat.” So “there is no discrimination at this point going on, is there?” Komer claimed that the Montana Supreme Court itself discriminated against religious students by shooting down the tax credit program. Does that mean, Justice Sonia Sotomayor wondered, that Montana has “to keep the program alive?” Yes, Komer said: Once “the state chose to give aid,” it could not stop giving aid to refrain from helping parochial schools.

This claim is, to put it mildly, a stretch. There is some precedent for the idea that states can’t deny funding to religious institutions because they are religious. In 2017’s Trinity Lutheran v. Comer, the court held that Missouri violated free exercise by refusing to let a church daycare center compete for a grant to resurface its playground. The exclusion of a church from a public benefit “solely because it is a church,” the court declared, “is odious to our Constitution.” But Trinity Lutheran was explicitly limited to “express discrimination based on religious identity with respect to playground resurfacing,” and disclaimed any impact on “religious uses of funding.”

Everyone agrees that religious schools, unlike the daycare center, will use taxpayer money to indoctrinate students. So Komer’s argument is pretty radical, a far cry from Trinity Lutheran. Just how radical? In his brief, Komer wrote that a student may not be “forced to choose between attending a school that accords with her beliefs or receiving thousands of dollars in government benefits.” But doesn’t that mean states have to fund religious education in par with public education? Komer’s claim would seem to give every child a First Amendment right to attend religious schools on the taxpayer’s dime.

Justice Stephen Breyer raised this point with Jeffrey Wall, principal deputy solicitor general, who supported the plaintiffs. If a state spends $500 million on public education, Breyer asked, does it have to give the same amount to parochial schools? Wall said no, but Breyer wasn’t satisfied. “What,” he asked, “is the difference?” Chief Justice John Roberts—who was remarkably perky given his side hustle presiding over the Senate’s impeachment trial—had the same question. He asked Adam Unikowsky, who represents Montana, whether Komer’s theory “leads to a situation where the funding that goes to public schools” would “have to go to religious schools,” as well. Unikowsky wasn’t sure, but the chief seemed troubled by the possibility.

Predictably, Justices Samuel Alito and Brett Kavanaugh went to bat for Montana’s religious families, framing them as victims of appalling discrimination. Kavanaugh told Unikowsky that “grotesque religious bigotry against Catholics” was the “clear motivation” for Montana’s ban on sectarian aid. But as Unikowsky told Kavanaugh, Montana’s ban was enacted in 1972, not to burden religion but to protect it from state interference. Thirty-seven states have similar provisions in their constitutions, and school choice proponents assert that they were motivated by anti-Catholic bias. It’s true that Reconstruction-era nativists favored these provisions—but so did advocates for universal education regardless of creed.

Alito tried a different angle: Imagine if a state shut down a scholarship program because money was “mostly going to blacks and we don’t like that.” If that’s unconstitutional—and it surely is—isn’t it also unconstitutional to shut down a program because money went to religious schools?

“We just don’t think that race and religion are identical for all constitutional reasons,” Unikowsky said. “Basically, what you’re saying,” Alito snapped, is that “the difference between this and race is: it’s permissible to discriminate on the basis of religion.” Breyer jumped in to help: “Yes,” he said, “race is different from religion. Why? There is no establishment clause in regard to race. What is the establishment clause? Well, it has something to do with not supporting religion. And there is nothing more religious, except perhaps for the service in the church itself, than religious education.”

Here, Breyer came the closest of any justice to acknowledging a foundational principle oddly obscured in this case: The Constitution mandates the separation of church and state for good reason. Stillwater Christian School, where the plaintiffs send their children, inculcates students with a theology-based anti-LGBTQ ideology. So do at least three other schools that participate in the scholarship program, as HuffPost reported on Thursday. One places “homosexual and lesbian behavior” in the same category as “incest” and “bestiality” while stating that no “non-Christian” or “uncommitted Christian” could teach there. Another expels students on the basis of “lesbian, gay, bisexual and/or transgender conduct” and requires employees “to affirm that they have not and will not engage in such behaviors.”

Christian schools have a right to teach this ideology, and Christian parents have a right to send their children to these schools. But shouldn’t Montana taxpayers also have a right not to subsidize these teachings, which may violate their own religious beliefs or freedom of conscience? Can’t state embrace the principles of the establishment clause by declining to compel residents to fund faiths that clash with their own beliefs? If parents want their children to learn that same-sex intimacy is no different from bestiality, is everyone else obligated to help pay for those lessons?

The fate of Espinoza lies, as usual, in Roberts’ hands. Because the chief seemed concerned about the alarming implications of the plaintiffs’ argument, he might join with the liberals to throw out the case. But it’s just as likely that the five conservatives will order Montana to revive its tax credit scheme and proclaim that once states give money to private schools, there’s not takebacks because religious schools would otherwise face discrimination. That outcome might appear narrow, because it does not force states to fund religious schools in the first place. But it would actually constitute a revolutionary rewrite of the First Amendment. However this case turns out, it is only a matter of time before the court’s conservatives again manipulate the free exercise clause to finance religious exercise with taxpayer money.