The case of transgender teenager Gavin Grimm drew national attention last year when it was on the brink of being heard by the Supreme Court, before being remanded.

But now, a lesser-known case out of Boyertown, Pennsylvania, that has been working its way up the judicial ladder could become the first one heard by SCOTUS that directly addresses the issue of transgender rights—and specifically restroom protections.

Unlike the Grimm case, which challenged a school district policy that barred the young man from using the boys’ bathroom, Joel Doe v. Boyertown is a direct challenge to a school district that currently allows transgender students to use facilities matching their gender identity.

The lawsuit, filed on behalf of cisgender students at Boyertown Area High School who oppose the school’s trans-inclusive policy, has already failed before the Third Circuit Court of Appeals, which ruled in favor of the school district this June.

But as The Morning Call reported Tuesday, conservative legal group Alliance Defending Freedom filed a petition this week asking the Supreme Court to review the Third Circuit ruling, arguing that the case would be “an ideal vehicle for this Court to address whether school locker room and restroom policies like Boyertown’s are constitutional.”

Simply put, they want the Supreme Court to weigh in on bathrooms, once and for all.

If the Supreme Court grants the review, hears the case, and issues a ruling, it would mark the first time that the judicial body has touched on transgender rights.

Several federal-level courts have ruled that existing bans on sex discrimination—under Title VII and Title IX—cover transgender people, but that logic has yet to be upheld at the very highest level, nor has it been expressly and explicitly written into civil rights law.

All of which means that the Supreme Court’s handling of this case could have enormous consequences not just for transgender students, but for all transgender Americans.

There are, broadly speaking, three possible outcomes: The Supreme Court could simply decide not to hear the case, which would uphold the lower Third Circuit ruling. That would be just fine by Ria Tabacco Mar, senior staff attorney for the American Civil Liberties Union, which in 2017 intervened in the Boyertown case on behalf of now-graduated transgender student Aidan DeStefano.

“ There are only a handful of cases like this. They have all gone the same way—and that is to rule in favor of inclusion ”

“We certainly don’t think that there’s a need for the Supreme Court to step in,” Mar told The Daily Beast, pointing out that most courts that have been asked to conclude that transgender protections violate the rights of cisgender students have not done so: “There are only a handful of cases like this. They have all gone the same way—and that is to rule in favor of inclusion.”

The other two outcomes involve SCOTUS actually hearing the case and issuing a ruling: They could rule against the plaintiffs, which would effectively have the same force as deciding not to hear the case. LGBT advocates would welcome that ruling, although its shape and scope would vary, depending on the opinion itself.

For instance, it’s far more likely given the legal questions posed by this case that the Supreme Court would say that local school districts like Boyertown cannot be barred from establishing transgender protections than it would be for the Justices to affirm that all transgender students nationwide are protected under Title IX. (Grimm’s case might have provided that latter opportunity.)

But even that more scaled-back ruling would be a milestone in the Trump era.

“Certainly, it would be helpful to have the Supreme Court send a message that there is absolutely nothing wrong with schools deciding to treat transgender students equally,” Mar told The Daily Beast. “I think they could send the same message by simply voting not to hear the case at all, because of course that’s what the [Third Circuit] court here did and that’s what other courts around the country have done.”

There’s another outcome that has the potential to be catastrophic for a generation of transgender students: The Supreme Court—now with a conservative majority and two Trump picks—hears the case and agrees that transgender students cannot be protected by school policies. In the worst case, they agree that Title IX not only doesn’t protect transgender students, but actually requires schools to discriminate against them.

Citing the language of Title IX, the ADF’s petition argues, “When a school policy opens all school locker rooms and restrooms to members of the opposite sex”—a reference to transgender people—“a student that reasonably feels embarrassed and harassed and can no longer use the facility has been denied access ‘on the basis of sex.’”

This is, in Mar’s estimation, “an attempt to use Title IX as a sword rather than a shield against discrimination.” In essence, the argument is that the real sex discrimination is the discrimination against cisgender students who are so appalled by the presence of transgender students that they can no longer use the same bathroom as them.

For a court to go along with that logic would, Mar believes, be “pretty extreme,” especially considering the many federal courts that have already affirmed that sex discrimination bans cover transgender people. In fact, Mar thinks this case would be “easier to win” in terms of legal strategy than the Grimm case would have been.

But it’s certainly within the realm of possibility for the Supreme Court to issue a broad, anti-transgender ruling—and that should alarm a community that’s already under attack. As Mar put it: “I think this case has the potential to be devastating.”

It would be even more so on top of the many attacks on the transgender community from the Trump administration—most pertinently, the February 2017 rescinding of an Obama-era “Dear Colleague” letter instructing schools to consider transgender students protected under Title IX.

Ever since that letter was rescinded—effectively sending Grimm’s case back down to the circuit-level shortly thereafter—it has been up to local districts like Boyertown to decide whether or not to adopt transgender-inclusive policies.

Schools that don’t adopt those policies—or that even adopt anti-transgender policies—have seemingly very little to fear under the Trump administration, given the Department of Education’s reported inaction on transgender discrimination claims.

In this context, for the Supreme Court to decide that transgender-inclusive policies violate the privacy of cisgender students would reverse years of local-level progress.

“We are talking about a decision that’s just devastating to the thousands of trans kids who are in school, who are already finding themselves under attack by our federal government, certainly by the White House,” said Mar. “For the judiciary to sort of glom onto that attack would be really challenging.”

Given how hard it would be to undo a ruling like that—which would involve waiting for the balance of power to potentially shift in the Supreme Court—Mar believes the petition only underscores the importance of a legislative solution for transgender equality.

After all, none of these judicial tussles over the interpretation of “sex” under Title VII and Title IX would be necessary if Congress simply added sexual orientation and gender identity as a protected characteristic under federal civil rights law.

That’s what a federal bill known as the Equality Act would accomplish—and, at this point, it could be the only guarantee that a judiciary increasingly shaped by the Trump administration doesn’t roll back decades of progress for transgender people in the courts.

Regardless of how the Supreme Court handles the petition, Mar says, its mere existence should put pressure on Congress to protect transgender people sooner rather than later.

“I think just the fact that claims like this are being advanced under Title IX should be a real wake-up call to Congress about why the Equality Act is needed,” she said.