A Christian legal advocacy group asked the U.S. Supreme Court this week to rule that employers can legally discriminate against transgender people in the workplace.

If the Court decides to hear the case and then issues a bad ruling, it will have far-reaching consequences beyond employment law. It could bring about the decimation of civil rights for LGBTQ people in this country.

The case itself, R.G. & G.R. Harris Funeral Homes v. EEOC, is fairly straightforward. Thomas Rost, the owner of Harris Funeral Homes, fired Aimee Stephens, a transgender woman, when Stephens told Rost that she would be presenting as a woman at work. Stephens filed a claim with the Equal Employment Opportunity Commission (EEOC)—the federal agency charged with investigating and litigating employment discrimination cases—and after an investigation, the EEOC filed a lawsuit against the funeral home on Stephens’ behalf. The Sixth Circuit Court of Appeals ruled in her favor. Now, if the Supreme Court decides to take the case, it will decide whether or not Title VII’s ban on employment discrimination covers transgender people. Sounds simple enough.

But the case isn’t simple. It’s a way for Alliance Defending Freedom (ADF)—which the Southern Poverty Law Center has called a hate group because the firm spreads ludicrous conspiracy theories about a vast “homosexual agenda”—to turn its anti-LGBTQ fantasies into a reality. ADF’s lawyers have turned the weaponization of religion into a cottage industry. Their goal is to strip LGBTQ people of their civil rights by prioritizing religion over their humanity.

One strategy ADF is using to do so is to target federal civil rights laws like Title VII of the Civil Rights Act of 1964. In 2012, the EEOC decided in a case called Macy v. Holder to fold transgender people into the protections offered by Title VII when it ruled that Title VII prohibits discrimination not just “because of sex,” but also on the basis of gender identity.

The decision wasn’t a leap. In 1989, the Supreme Court ruled in Price Waterhouse v. Hopkins that Title VII’s ban on discrimination “because of sex” applies not just to biological sex, but also to gender stereotyping—discrimination based on someone failing to act and appear according to expectations defined by gender.

Legally, it follows, then, that transgender people aren’t conforming to arbitrary societal standards about how people assigned male or female at birth are supposed to look and behave. That’s what Judge Karen Nelson Moore essentially wrote in her opinion for the Sixth Circuit Court of Appeals backing Stephens: “[A]n employer cannot discriminate on the basis of transgender status without imposing its stereotypical notions of how sexual organs and gender identity ought to align,” she wrote.

Certainly, when Congress passed Title VII in 1964, it was not contemplating gender identity discrimination. But that doesn’t matter. As a wise man once said, “Statutory prohibitions often go beyond the principal evil to cover reasonably comparable evils, and it is ultimately the provisions of our laws rather than the principal concerns of our legislators by which we are governed.”

That’s Justice Antonin Scalia writing the majority opinion in Oncale v. Sundowner Offshore Services, a case involving male-on-male sexual harassment. Scalia noted that “male-on-male sexual harassment in the workplace was assuredly not the principal evil Congress was concerned with when it enacted Title VII.”

Almost assuredly, neither was discrimination against a transgender employee. But that doesn’t mean firing them is not a “principal evil” prime for redress under Title VII. Still, ADF insists that Rost had the legal right to fire Aimee Stephens because she is trans.

But, you may be wondering: The EEOC is a federal agency. And if that agency says that Title VII bars discrimination on the basis of gender identity, then that should be the end of the discussion, shouldn’t it?

Well it is—for now. Under current law, a court must defer to the EEOC’s interpretation of its own regulations. That’s because of something called Auer deference, from the 1997 case Auer v. Robbins. In that case, the Supreme Court ruled that federal agencies are entitled to interpret their own regulations as they see fit, as long as their interpretation isn’t erroneous and doesn’t conflict with the plain language of the statute or regulation.

This has been good news for transgender people over the last several years. The EEOC has interpreted Title VII to include trans people. The Department of Education (DOE) has done the same when it comes to Title IX of the Education Amendments Act of 1972, which prohibits discrimination under any education program or activity that receives federal funding; the DOE under the Obama administration required schools that receive federal funding to guarantee transgender students access to the appropriate restrooms and facilities.

Unfortunately, an even more conservative Court (which the Supreme Court will be once Justice Anthony Kennedy is replaced) is not likely to rule in favor of trans or gay people. That’s because the Court is unlikely to accept the EEOC’s interpretation of Title VII. Conservatives on the Court have been gunning for Auer deference, looking for an opportunity to end judicial deference to agency interpretation. This case might present that very opportunity.

Should the Court opt to hear the case during the upcoming term and decide to stop deferring to the EEOC’s interpretation, that means trans people will no longer have any federal protection from discrimination in the workplace. This could, in turn, undercut the power of all other federal agencies to interpret their own regulations—for example, the Department of Education might be forced to stop interpreting Title IX as providing protection to transgender—thus leaving vulnerable people with fewer avenues of recourse when they experience bigotry.

CORRECTION: This piece has been updated to clarify ADF’s arguments in the petition for writ of certiorari submitted to the Supreme Court on behalf of Harris Funeral Homes. ADF made, and lost, the argument in the Sixth Circuit Court of Appeals that employing Stephens was a substantial burden on Rost’s religious freedom under the Religious Freedom Restoration Act, but did not make that argument in the petition to the Supreme Court.