“You’re doing fine, Oklahoma,” proclaimed the 1943 Broadway musical. Soon, the Supreme Court might disagree.

On Wednesday, it will hear oral arguments about an Oklahoma dispute involving the tension between the First Amendment’s proscription of the “establishment” of religion and its guarantee of the “free exercise” of religion. And about whether charter schools are “state actors.” Specifically: Is an explicitly Catholic charter school an extension of the state government, or is it a private entity contracting with that government?

Oklahoma charter schools, none of them religious, serve about 7.2 percent of the state’s public school pupils. They are operated by private entities. In 2022, the Supreme Court held that Maine had unconstitutionally discriminated against religion by excluding religious schools from participating in the state’s school choice voucher program. So, the Catholic Church in Oklahoma asked to participate in the state’s charter school program with the St. Isidore of Seville school, which says it “fully incorporates” church dogma in “every aspect” of the school — e.g., students are expected to adhere to the belief that “Christ is present in the Holy Eucharist.”

Charter schools are public in that they receive state funds and are open to all children. Like private schools, however, they can be created by private initiative and enjoy wide exemption from public school districts’ policies regarding curriculum, admissions, hiring and operations.

The court has held that the Constitution’s free exercise guarantee forbids government rules that require religious groups to choose between living their faith and being eligible for a government benefit by collaborating with government in providing social services, including education. Furthermore, because the nation’s many governments lack the resources to perform all the tasks they think necessary, they subsidize, often substantially, private organizations, many of them faith-based.

In the debate about St. Isidore, there is awkwardness all around. For decades, public school advocates have said charters are private schools siphoning resources away from public education. Charter advocates have responded that charters are public schools. Now both sides have executed semantic somersaults, with charter advocates saying their schools are private, meaning not state actors, and critics saying the charters are state actors, and hence not private.

When religion becomes part of the debate, new antagonisms mirror old ones. Oklahoma’s attorney general, before he persuaded the state Supreme Court to rule against St. Isidore, warned the head of Oklahoma’s charter school board that approving St. Isidore would require also approving charters run by all faiths, including Islam, adding that “most Oklahomans” consider non-Christian faiths “reprehensible.”

The U.S. Supreme Court has held that once government elects to fund a private activity, as Oklahoma does regarding access to private schools, it cannot disqualify some entities “solely because they are religious.” Victory for St. Isidore might, however, stall the impressive momentum of the national charter school movement.

None of the 45 states with charter schools has religious ones, and many leading advocates of charters oppose bringing religious schools into their ranks. This is understandable, given the fierce historical disputes that still simmer in America, disputes that might derail the charter movement. Michael J. Petrilli of the Thomas B. Fordham Institute and Stanford’s Hoover Institution anticipates years of litigation unless the high court, while siding with St. Isidore, simultaneously answers numerous thorny questions:

“The main one is whether religious charter schools will be allowed to prioritize members of their faith when admitting students. (Charter schools generally have to take all comers and hold a lottery if oversubscribed.) Also, will they be allowed to exclude children or families that don’t abide by their values, including LGBTQ students or families? Could they hire only adherents to their religion as teachers and other staff?”

A Supreme Court victory for St. Isidore would enable opponents of charters and other forms of school choice to warn that government entanglement with religion inevitably brings intense disputes about religious demands for exemptions from generally applicable laws pertaining to, for example, nondiscrimination in hiring.

More than a million pupils nationwide are in private schools with financial assistance from states’ school choice programs. Nearly 4 million pupils attend 8,000 charters. Nina Rees, writing for Education Next, says that during the coronavirus pandemic’s school closures, regular private schools lost 1.4 million students, while charters attracted almost 450,000 new families.

School choice — the great civil rights issue of our day — has advanced dramatically in red states. But expanding in blue states, where teachers unions are powerful and implacably opposed, would become even more difficult in the wake of a St. Isidore victory.

George Will writes a column for the Washington Post.