Which religious practices has the supreme court found to violate the “wall of separation?”

For decades, First Amendment expert Charles Haynes has advised public schools and other groups on how to manage the balance between Americans’ right to religious expression and their right to freedom from government-imposed religion. He literally wrote the book on the topic for the U.S. Department of Education along with partners as diverse as the National Association of Evangelicals and the American Civil Liberties Union.

But in recent weeks, after the Supreme Court ruled for Maine parents looking to use taxpayer dollars for religious school tuition and for a Washington football coach who led students in public prayer, Haynes says he is at a loss for what to tell those he consults.

“What am I supposed to say now? What do I say? ... We’re now at the point where you wonder if there is any Establishment Clause left,” he said of the portion of the First Amendment that bars laws “establishing” religion.

The high court this term sped up a process it has been working at for at least a decade: shrinking the wall of separation between church and state.

At a time when America is becoming more religiously diverse, unaffiliated and secular, major rulings have rewritten decades of precedent and given victory after victory to religious petitioners seeking more voice, money and access in the public square. Many have been conservative Christians who argued they had been unconstitutionally shut out.

With the door opened much wider, the question many experts are asking now is: Has the court ushered in a period of more pluralism for people of all religious faiths and none, or instead codified government power and privilege for those in the majority?

“Is this good for pluralism? On paper, the answer is yes. Practically, no,” said David Callaway, who has trained thousands of teachers and coaches, including across the Bible Belt, through his work for the Religious Freedom Center. “Technically the [Maine school funding] ruling allows more money to go to a Muslim school, too, but if there were enough Muslim families to support a school, that would have been explored. The benefits will mostly go to the majority. It’s a disadvantage for minority faith.”

Justices across the political spectrum from the mid-1900s until the past couple of decades mostly agreed that keeping government officials, institutions and money disentangled from religion protects the Constitution’s promise of religious freedom — including for religious minorities — and helps avoid strife. Critics of that view, mostly religious conservatives, began in the 1980s to push back and slowly to start winning. Those critics — now represented by the court’s majority — say the earlier understanding discriminated against religious people and organizations, that recent history is a distortion and that the Constitution’s concern about the “establishment” of religion was about keeping the government from interfering with religious matters, not about limiting religion in public life.

High-profile attacks on the modern order are becoming more common. Justice Neil M. Gorsuch, during oral arguments earlier this year in a case about a Christian flag flying over Boston City Hall, wondered about the “so-called separation of church and state.” A little over two weeks ago, Rep. Lauren Boebert (R-Colo.) told a crowd she is “tired of this separation of church and state junk.”

Experts say it’s unclear what will happen next. Among the most-watched questions is whether a flood of religious schools — including those that violate anti-discrimination laws protecting LGBTQ people — will seek and secure public funding. The Free Beacon, a conservative news site,wrote that the ruling “may precipitate a historic expansion of public aid to families who favor religious education.”

Other questions include: Will majority justices who in recent decisions said the primary guide in such cases must be “history” continue to open the door to religion in public spaces, including teacher-led Protestant prayer that was common for much of the country’s history? (Nearly half the country identifies as Protestant.) Or will repeated rulings for conservative Christians help them feel less threatened by growing diversity and cool down tensions?

“The big question is what unfolds over the next 10 years,” said Eboo Patel, leader of the Chicago-based Interfaith America, a nonprofit that promotes interfaith cooperation, especially on college campuses.

“What could be good about the Washington state ruling and Maine ruling is they speak to a more pluralistic public square when it comes to religious expression. Is it possible that a Christian football coach holding public prayer feels coercive? Yes, and that’s not good. It is also possible that it leads to more diverse expression, too,” Patel said.

Debates about the government-religion relationship, and even what constitutes “religion,” go back to the earliest U.S. colonies.

“Those have been moving targets for a very long time. The law of church and state has not been stable. We have been changing all along,” said Sarah Barringer Gordon, a University of Pennsylvania historian of church-state law.

But contemporary debates picked up around 80 years or so, as the Supreme Court began ruling that constitutional amendments that initially applied only to the federal government also applied to states. The core religion issues center on two clauses in the First Amendment; the Establishment Clause, which bans the government from “establishing” a religion; and the Free Exercise Clause, which protects citizens’ right to practice their religion.

What exactly they mean, how they interact and what limits there should be on either are the variablesthat have increasingly been reset by the Supreme Court in the past decade or so. The court has been expanding free exercise and reversing cases where lower courts had limited religion, citing establishment violations.

An analysis of religion cases before the court was published a year ago by the journal the Supreme Court Review and found the change has been most dramatic in the leadership era of Chief Justice John G. Roberts Jr., which began in 2005.

The analysis, by law professors Lee Epstein and Eric A. Posner, found that the Roberts Court has ruled in favor of religious organizations more than 81 percent of the time, compared with “about 50 percent for all previous eras since 1953,” the article said.

The article touches on the major concern of the new majority’s critics: religion clauses long meant to protect minorities and ensure religious liberty in America being flipped on their head in recent decades by a segment of the Christian majority who feel threatened.

“In most of these cases, the winning religion was a mainstream Christian organization, whereas in the past pro-religion outcomes more frequently favored minority or marginal religious organizations. A statistical analysis suggests that this transformation is largely the result of changes in the Court’s personnel,” the analysis reads.

Kim Colby, director of the Center for Law and Religious Freedom at the Christian Legal Society, said a “corrective” has been needed since the 1980s when it comes to Christians.

“Maybe it’s Christians who are bringing the cases, but it can’t be that school districts, as the government, give free passes to some faiths in what they wear and do as far as religion in public schools and then say to Christians: ‘You can’t do that,’ ” she said. Asked if she felt minorities do get to do things the majority doesn’t, she said sometimes school administrators are more loose — possibly wandering into Establishment Clause violations — with minorities while being stricter with Christians: “I think there’s a blind spot from school administrators: They’re less likely to see an Establishment Clause issue with faiths that they consider kind of new.”

The court’s recent rulings and dissents embody disagreement over the meaning of the “separation of church and state” and who is really representing the “history and tradition” of the nation.

The “separation” term is understood to describe the religion clauses, and comes from a letter written by then-President Thomas Jefferson. Jefferson also wrote the state statute for religious freedom in Virginia that laid the groundwork for the First Amendment. He and James Madison, who introduced the Bill of Rights, both said state support for any particular religion — or religion in general — violated citizens’ natural rights.

“No man shall be compelled to frequent or support any religious worship, place, or ministry whatsoever ... nor shall otherwise suffer on account of his religious opinions or belief,” the Virginia statute reads.

“Nor shall the full and equal rights of conscience be in any manner, or on any pretext infringed,” Madison wrote.

While the majority points to “history,” experts disagree over which founders to emphasize and how to understand their words.

“Jefferson was an outlier among the founding generation, in terms of his views of traditional religious belief and his understanding of what church-state separation should mean,” Richard Garnett, a University of Notre Dame law professor who focuses on freedoms of religion and speech, told The Post in an email. “And Madison’s writings about state support for religion accompanied his firm commitment to the free exercise of religion.”

Garnett, a friend and former colleague of Justice Amy Coney Barrett, said the ruling in the football coach’s case “rejects the idea that the ‘strict separation’ version of secularism that the Court during the late-middle 20th century ... should trump longstanding practices.”

“The Court in the 1970s and 1980s created an overbroad version of the Establishment Clause’s prohibition. To correct that overbroad version is not to denigrate the Establishment Clause. In my view, that Clause is crucial and vital, and prevents governments from interfering with religious matters,” he wrote. People who criticize the court as weakening the Establishment Clause “are mistakenly assuming, as the baseline, an inflated version of the Establishment Clause.”

Other experts worry the rulings are unleashing chaos.

Holly Hollman, general counsel of the Baptist Joint Committee for Religious Liberty, said her group gets a lot more questions these days about what is legal, and that the nature of the two recent rulings will lead to what she sees as additional confusion.

In the case of the coach, she said, the law for decades had been “settled” and clear that teachers and students aren’t equal in terms of how their personal religious freedom plays out in a school context: Students, who are required to be there, can be coerced and pressured; teachers represent governmental authority.

“Here, the court seems singularly focused on the coach’s claim,” disregarding impacts on students, she said.

The clear majority of Americans support the separation of church and state, public opinion surveys show. What they mean by that varies, and strongly correlates to political party and stated religiosity.

In polling this fall, the Pew Research Center found that 19 percent of Americans said the federal government should stop enforcing that separation, compared with about 30 percent of “highly religious Christians.” Twenty-seven percent of those who identify or lean Republican said the government should stop enforcing church-state separation, twice the percentage of Democrat and Democrat-leaners who did.

Dozens of minority and Christian faith groups signed a brief to the court protesting the coach’s prayer in Washington, saying that “allowing the football coach to lead the team in prayers at football games undermines the freedom of conscience of student athletes — who may wish to refrain from joining the prayer but who may feel overwhelming pressure to please their coach.”

Critics of the court’s recent shift say it’s not the ideal of pluralistic expression that concerns them but rather the reality of a majority with new legal dominance.

The Supreme Court majority characterized the coach’s prayers much differently from those who dissented. The majority focused only on a few of Joseph Kennedy’s prayers in October 2015, that didn’t include his players, just before he was suspended. They said all that mattered were the incidents specifically cited by the school district, and didn’t find relevant the previous seven years of prayers, which included the majority of his own players as well as sometimes players from other teams, adults and media.

Justice Sonia Sotomayor included photos of those at midfield in her dissent.

The Supreme Court didn’t find that school officials are allowed to lead students in prayer. Instead, it found that Kennedy was technically off the clock — despite still being in uniform, on the 50-yard lane, with his players in uniform — so he wasn’t “acting within the scope of his duties as coach.” It called his prayers “private,” “personal” and “quiet.”

Just because prayers were public and players from varying teams joined in, Garnett said, doesn’t mean Kennedy was representing the government or anything official.

It’s this narrowing of relevant facts that some find very worrisome — and intentional.

“I think you first have to recognize there is no legal reason for the court to have taken this case. That decision is part of this newly constituted court’s endeavor to rewrite major areas of constitutional law — and especially defanging the Establishment Clause, making it mean less,” Hollman said.

Monica Miller, legal director at the American Humanist Association, said her group has seen an increase in complaints but a decrease in an ability to act on them because of an influx of judges who are less likely to see church-state violations.

“All secular organizations are beingvery cautious with which cases we bring. I wouldn’t bring the same cases I brought 10 years ago,” she said.

Andrew Seidel, spokesman for Americans United for Separation of Church and State, said the kinds of religion cases that courts are taking have flipped from those in earlier decades, which mostly concerned religious minorities, to cases today centered around “mainstream Christians.”

“America invented the separation of church and state. No other nation has sought to protect citizens’ ability to think freely, and we should be proud of that fact,” he said, noting the Constitution mentions no deity and bans any religious test for office. “We need a national recommitment to the separation of church and state.”

Amber Kost, a teacher and atheist from Bremerton, Wash., has a son who began high school the year Kennedy left. A nonbeliever, he didn’t feel comfortable discussing his beliefs with people outside the house, she said.

To her, the Supreme Courtmajority saying they would look to “history” is “like opening up their ability to decide how they want the case to go and just ignore facts that are in their way, and that’s kind of terrifying,” Kost said. “This opens the door for the majority faith to recruit in schools. ... I’m just beat up right now. People are genuinely so deflated. It feels like we’ve been swimming backwards.”

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