A view of the Supreme Court in Washington, D.C., on Oct. 14. Saul Loeb/AFP via Getty Images On Tuesday, the Supreme Court hears arguments in a case that pits the Catholic Church against taxpayer funded school programs for all 4-year-olds in Colorado. At issue is whether religious schools may refuse to admit the children of gay and trans parents in violation of a state law that bars discrimination.

The first line of the Bill of Rights says: "Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof." As early as the founding of this country, Thomas Jefferson described the clause as creating a "wall of separation between church and state." The Supreme Court formally embraced that idea in the 1940s, making it the law of the land — until roughly 10 years ago. That's when the court's new conservative majority made an increasingly dramatic doctrinal U-turn, focusing not on the separation of church and state, but on that second clause in the First Amendment: protecting the free exercise of religion.

"It's literally the opposite of what the law was not that long ago. It is just a complete shift," says Michigan State University law professor Frank Ravitch, who has written extensively about the Constitution's religion clauses.

To cite just one example, the Supreme Court, by an 8-to-1 vote, ruled in 1983 that that Bob Jones University should lose its tax exempt status because it prohibited interracial dating and interracial marriage on religious grounds, and that constitutes racial discrimination that the government money may not support. That said, it's unclear if the court will reach a similar conclusion now.

Why is that? Because race has a "unique" place in U.S. history, contends professor Douglas Laycock, emeritus professor of law at the University of Texas at Austin and the University of Virginia. "There's nothing like 250 years of slavery, civil war, 750,000 dead, three constitutional amendments. Nothing like that for any other group," he says.

As for the Colorado case, Laycock acknowledges that the Denver archdiocese is discriminating, but he adds, "The question is whether that discrimination is a protected exercise of religion." Rather than focusing on separation of church and state, the current court instead has focused on the rights of religious groups when pitted against state and federal laws that ban discrimination based on race, sex, religion or other categories.

It's the sex part that has thrown a monkey wrench into Colorado's broad program aimed at ensuring that virtually all 4-year-olds in the state get a pre-K education.

"The law really was about implementing a program that said we want every kid, no matter where you live, to be able to have access to universal preschool," says Steve Fenberg, who served as president of the Colorado state Senate when the pre-k program was enacted, complete with a $6,300 benefit for each child enrolled in the program every year, money that comes from a tobacco tax.

To accomplish that, the state did something most other states have not. It created a broad plan, including religious schools, as long as the schools abide by a state law that bars discrimination based on race, religion, sexual orientation or gender identity.

Colorado state Rep. Emily Sirota, a prime sponsor of the universal pre-K bill, emphasizes that the state wanted parents to have "a robust choice" about where their 4-year-olds would go to school.

Indeed, she notes that the Catholic Church initially endorsed the program, and Catholic Charities continues to participate, along with other religious groups, including at least 35 Christian schools, one Muslim and three Jewish schools.

"The caveat is that you can't discriminate, and you need to allow all students to participate," says former state Sen. Fenberg.

That caveat is where things went awry. The Denver Archdiocese and two parishes challenged the law in court, represented by the Becket Fund for Religious Liberty and its CEO, Mark Rienzi. He maintains that the Colorado law flatly discriminates against Catholic schools. "They're only excluding religious schools that are organized around beliefs that Colorado doesn't like.

And that's the constitutional problem," says Rienzi. "Not everybody has to be Catholic to show up, but they do have to agree to support Catholic teachings and not publicly contradict Catholic teachings. That's the way these schools are set up." Therefore, the church wants an exemption from the state's anti-discrimination law, which makes it illegal to refuse entrance to school for 4-year-olds whose parents or potentially other family members are gay or trans. Of course, not all Catholic programs march to the same drummer.

"I don't agree with the sky is falling," says Tim Uhl, who has held multiple leadership positions for Catholic school systems in seven states. He is currently the interim director of mission and ministry at Notre Dame High School in San Jose, Calif., and is among a group of Catholic school directors who has filed a brief siding with Colorado.

"We do admit students that are not Catholic and families that are not Catholic," Uhl notes, adding that non-Catholic families "understand that even if they don't agree with certain doctrine, that doesn't mean they're going to be disruptive … You know, diversity of opinion and diversity of thought is part of an educational experience."

But the archdiocese of Denver has a different viewpoint. In an article published in the Denver Post Archbishop James R. Golka wrote that as a result of the Colorado pre-K program, enrollment in Catholic schools is down 20% across the archdiocese and two preschools have closed, including one which serves "minority and low income families."

But the larger "tragedy," said the archbishop, is that "Colorado's attack on Catholic education threatens the broader culture. In our age of hyper- secularization, moral relativism, and technical reductionism, we urgently need schools that teach students who they truly are: immortal souls, beloved by God." Instead, he added, "The predictable result is a culture unmoored from truth, adrift in confusion."

Scott Elmer, superintendent of Catholic schools for the Archdiocese, says "it's very rare" for LGBTQ parents to try to enroll their children. "This is not something we deal with regularly," he adds.

That said, however, the Supreme Court's conservative supermajority, including President Trump's three appointees, have sent strong signals that they are headed toward revolutionizing religious rights in ways not widely embraced before.

Last year, the court was evenly divided as to whether taxpayer-funded charter schools could include religious schools and teachings. But because Justice Amy Coney Barrett recused herself over a potential conflict of interest, the justices dropped the case.

Now, the Colorado case is before the Supreme Court, and this time Barrett has not felt a necessity to recuse. So there will be a full court ready to decide the case.

"The question is, how far will the Supreme Court go in requiring the government to pay for religious schools?" asks Berkeley Law School dean Erwin Chemerinsky.

Then too, he observes, "there's the issue of will the government have to fund religious charter schools? … We don't know how far the court's willing to go." After all, charter schools were designed to be public schools that operate independently under a performance-based contract with state or local government agencies that provide taxpayer money for funding.

There are some 8,000 charter schools nationally, and roughly 276 in Colorado, and they have not, until now, been run by religious groups.

Just a few weeks ago, however, a federal district judge in Oklahoma allowed a taxpayer-funded Jewish charter school "grounded in enduring Jewish values" to open, using $2.6 million in state funding that is projected to grow to $8.3 million in state funds by 2030. The fate of the school remains in limbo Whether that continues and expands depends, of course, on the Supreme Court's decision in the Colorado case.