The biggest church and state case of the decade was heard at the Supreme Court on Wednesday: American Legion v. American Humanist Association. Given the court’s new conservative members, it’s quite likely that the result will be a huge symbolic victory for the religious right, rolling back decades of precedent on the relationship between church and state.

The question in the case is deceptively simple: Is a 40-foot-tall cross that sits in a Maryland traffic circle as a memorial to World War I dead a constitutionally acceptable secular monument, or an unconstitutional religious display?

Figuring out the answer couldn’t be more complicated.

The American Legion was responsible for erecting the memorial, now known as the Bladensburg Cross, back in 1925, but in 1961, the state of Maryland took ownership of it, and the land it sits on. It’s now part of a park filled with other, smaller memorials as well.

For liberals and secularists, it is a huge cross sitting on public land, owned by the public, maintained by public tax dollars. That’s a violation of the Establishment Clause, they say, because the government is paying to promote Christianity. It seems to “endorse” Christianity, to cite one of the magic words the Supreme Court uses in deciding these cases.

At oral argument, lawyers for Maryland and the American Legion made an array of arguments, some of which were more successful than others.

First, and most narrowly, they argued that the cross is really a secular memorial that merely happens to be “cross-shaped.” After all, the inscription doesn’t say “Jesus Saves”—it honors the war dead. But at oral argument, Justice Sonia Sotomayor, herself a Catholic, noted that to call the cross a secular symbol is blasphemous to many Christians.

“ In Justice Thomas’s America, Alabama could designate Evangelical Protestantism as the official state religion, and teach the resurrection of Christ in public schools. ”

Second, and more broadly, they argued, the cross doesn’t coerce anyone to practice religion. Maybe it is a religious symbol, but unless someone is being forced to do anything, it isn’t unconstitutional. Chief Justice Roberts and Justice Gorsuch objected to this test because it seemed little different from the Court’s “endorsement” inquiry, and seemed to depend too much on specific factual circumstances.

Third, and still more broadly, they argued that religious symbols like this are part of American history and tradition, and that history trumps any principled ideological argument. Even if the cross memorial is a religious symbol that appears to endorse religion, so is “In God We Trust”; so are the crosses in Arlington cemetery; so are the religious displays that have been found constitutional (including the Ten Commandments display from 2005) over the years.

Perhaps surprisingly, a variation on this argument resonated with the Court's conservatives and liberals. Justice Breyer, with Justice Kagan appearing to agree, suggested that perhaps it's acceptable to leave in place a cross erected in 1925, but it would not be acceptable to erect a new one now. This compromise would allow the Bladensburg Cross, and other extant memorials, to remain, while acknowledging that, in Justice Kagan’s words, “there’s something quite different about this historic moment in time.”

Most broadly of all, some, including Justice Thomas, have argued that the Establishment Clause itself—which, after all, only prohibits the government from “making laws respecting an establishment of religion”—has been wildly over-expanded over the last half-century. Even if the cross is a sectarian symbol that indeed endorses Christianity, that’s not the same as establishing religion.

The main reason American Legion has liberals worried is that these latter theories were fringe ideas as recently as two decades ago. But with Justices Thomas, Gorsuch, Alito, and Kavanaugh now sitting on the Supreme Court, they could well become law.

All four men have made comments over the years that they view the last 70 years of Supreme Court jurisprudence—beginning with 1947’s Everson v. United States decision, which first applied the Establishment Clause to the states—as unfaithful to the “original intent” of the Constitution’s framers and to the character of the United States as, if not quite a Christian nation, then a nation founded on “Judeo-Christian” values (whatever that means).

Indeed, Justice Thomas once opined that the Establishment Clause shouldn’t apply to the states at all. Consider that for a moment: in Justice Thomas’s America, Alabama could designate Evangelical Protestantism as the official state religion, and teach the resurrection of Christ in public schools.

And two years ago, Justice Gorsuch wrote that the government should be allowed to fund religious facilities because it’s impossible to distinguish between what is religious and what is secular in the lives of religious people.

Remember, too, that Justices Kavanaugh, Gorsuch and Alito were all put up for the job by the Federalist Society’s Leonard Leo, an extreme conservative who has said that “I would love to see the courts unrecognizable” as a result of his work.

Certainly, the world envisioned by Justice Thomas is just that. And if you count the votes, it could actually come to pass.

Thus, while the immediate result is symbolic, a host of practical consequences would soon follow.

First, cases like these have long motivated the Christian right to vote, donate, and agitate for political and legal change. For example, the precursor to the Bladensburg Cross case is a more famous war memorial in San Diego, the Mount Soledad Cross. That monument, a huge cross that towers over the city, was found to be unconstitutional in 2011, a decision that was used in religious right marketing campaigns for years. (In 2015, the Mount Soledad Cross was sold to a private organization, and the Ninth Circuit declared the case moot.) It was a focal point of the successful campaign to redefine “religious freedom” to include the power to turn gay people away from businesses and deny health insurance to women.

The Mount Soledad Cross is “just” a symbol, but it is a symbol that has had real-world effects for thousands if not millions of Americans whose rights have been rolled back. Without the Mount Soledad controversy motivating the Christian right to action, there would likely not have been the Masterpiece Cakeshop case, which has enabled some businesses to turn away LGBT customers, or Hobby Lobby, which allowed businesses to refuse to provide contraception insurance.

If the court turns rightward in American Legion, GOP state legislatures could move quickly to create religious displays, push the envelope on prayer in schools, and further move the needle on government support of religious organizations. To take but one example, one case percolating through the courts now is about a high school football coach who led a public, but personal, prayer on the 50-yard line at the end of every game. If the American Legion were to win on broad grounds—rather than the narrow ones proposed by Justice Breyer—the coach will likely win as well, and communal prayers at school sporting events will become ubiquitous.

Indeed, conservative claims that the Bladensburg Cross is just an innocuous symbol are undermined by other conservative claims that the United States is a nation founded on Christianity and dependent upon Christianity for its moral center—a view once espoused by the present attorney general, William Barr. Which is it: neutral symbol, or symbol of a Christian Nation?

Deciding that question, ultimately, is the purpose of lawsuits like American Legion. And given the changes to the court’s makeup, liberals are right to worry that 70 years of church-state separation are about to buried beneath a 40-foot cross in Maryland.

Editor’s Note: This article has been updated following oral arguments in the case.