The handwriting on the wall came during a nearly two-hour argument involving a challenge brought by two Maine families to the state's unusual way of providing public education.

Transcript

MARY LOUISE KELLY, HOST:

Today, the U.S. Supreme Court's conservative supermajority seemed poised to hand school choice advocates a big victory. As NPR legal affairs correspondent Nina Totenberg reports, that could mean a very big expansion of state programs that are required to fund religious education.

NINA TOTENBERG, BYLINE: Maine is a state so rural that a majority of school districts don't have a high school. The way the state has dealt with that problem is to contract with existing public high schools to take kids from the districts with no high school and to pay the same amount to nonsectarian private schools to take up the slack as well. What the state will not do is pay tuition for students attending religious schools. School choice advocates have long sought ways to promote equal treatment for religious schools with taxpayer funds, and they had a willing audience today from the court's six conservatives, five of whom attended religious schools. All signal that they, too, view Maine's refusal to fund religious schools as unconstitutional.

The court's liberals noted that in the past, the court has said states may have voucher programs that allow parents to send their kids to religious schools, but that in this case, school choice advocates are asking the court to require that states must treat religious schools the same way they treat nonsectarian private schools. Justice Breyer suggested that in this case, beliefs taught in a religious school seemed to conflict with the state's human rights law.

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STEPHEN BREYER: No gay students, no gay teachers, man is superior to woman and a few other things like that.

TOTENBERG: Justice Sotomayor added that the Maine program treats everyone equally. The state provides a free public secular education for everyone, and if a family wants something different - namely a religious education - they have to pay for it.

That's definitely not the way the court's conservatives saw things. Justice Thomas asked Maine Deputy Attorney General Christopher Taub for his definition of a public education. Answer - an education that doesn't prefer one religion over another and doesn't teach through the lens of a religion. Chief Justice Roberts.

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JOHN ROBERTS: Let's suppose you have two schools. School A is run by religion A, and that religion has a doctrine that they should provide service to their neighbors. Religion B also has a school, but its doctrine requires adherence to educate children in the faith. Now, would the first school get the funds?

CHRISTOPHER TAUB: Yes.

ROBERT: OK. Would the second school?

TAUB: No.

ROBERT: So you're discriminating among religions based on their belief.

TOTENBERG: Justice Gorsuch chimed in.

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NEIL GORSUCH: How does that not discriminate against minority religious viewpoints in favor of religions that are more watered down?

TOTENBERG: Taub replied that under Maine's program, no school that instills religious beliefs is eligible for tuition payments from the state.

The hypotheticals continued. Would the state pay tuition for a school that taught white supremacy? No, said Taub. The school has to provide an education roughly equal to that in public schools. Justice Kagan, trying to rescue Taub, asked, what has been the hardest case the state has actually had? Taub replied there have not been any because the religious schools that have even asked about eligibility all identified themselves as religious and teaching through the lens of religion. Justice Kavanaugh repeatedly suggested that both religious and nonreligious schools should be treated the same way.

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BRETT KAVANAUGH: Discriminating against all religions versus secular is itself a kind of discrimination that the court has said is odious to the Constitution.

TOTENBERG: What about a school that's anti-religion? he asked. Would that school be eligible for the state tuition payments? Taub replied that he'd never heard of such a school in Maine, but it would not be eligible. Justice Barrett followed up.

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AMY CONEY BARRETT: How would you even know if a school taught all religions are bigoted and biased?

TOTENBERG: Taub replied that all but 0.2% of the children in Maine go to either a public school or 1 of the 11 nonsectarian private schools that have student bodies that are 95% publicly funded. So the state Department of Education, he said, is very familiar with what they teach.

Nina Totenberg, NPR News, Washington.

(SOUNDBITE OF MUSIC) Transcript provided by NPR, Copyright NPR.