On the campaign trail, Donald Trump said that he will protect “L, G, B, T … Q” people, even posing with the LGBTQ flag to signal that he’s a different kind of Republican on these issues.

Yet on Wednesday, Trump made it clear this was solely campaign talk. With a letter sent out by his administration, Trump rescinded an Obama-era guidance, which was issued in May 2016, protecting transgender students in public schools, arguing that this is an issue that should be left to the states and that the previous administration had gone too far in its interpretation of federal civil rights laws.

The public discussion around the letter focused a lot on bathrooms, since the guidance in question asked public schools to let trans students use the bathroom and locker room that aligns with their gender identity.

But while bathroom access is very important to trans people, the guidance was about much more — rooted in a discussion about the scope of federal civil rights laws and whether they should and do protect LGBTQ people. After LGBTQ victories in marriage equality and the end of “Don’t Ask, Don’t Tell,” transgender rights and protections are the biggest LGBTQ issue of our time. And Trump has made his position clear: He won’t use existing federal civil rights laws to explicitly protect trans people, much less other LGBTQ people.

This is the big LGBTQ issue of our time

Under most states’ laws and federal law, LGBTQ people aren’t explicitly protected from discrimination in the workplace, housing, public accommodations, and schools. This means that a person can be fired from a job, evicted from a home, kicked out of a business, or denied the correct bathroom facility just because an employer, landlord, business owner, or school principal doesn’t approve of the person’s sexual orientation or gender identity.

In a world where marriage equality is the law of the land and LGBTQ people can serve openly in the military, the gap in nondiscrimination laws is treated by advocacy groups as the big remaining civil rights battle for LGBTQ people.

Trump, to some credit, maintained some protections for LGBTQ people — specifically, executive orders by former President Barack Obama and former President Bill Clinton that prohibit federal employers and contractors from discriminating against LGBTQ people. It would, however, be unprecedented for a president to revoke these kinds of orders; former President George W. Bush, for example, didn’t revoke Clinton’s orders protecting gay people.

Trump also hasn’t moved to shield the rest of the LGBTQ population from discrimination, leaving LGBTQ people unprotected if they’re not employed in some way or another by the federal government. And his decision to revoke Obama’s guidance for trans students kills off one of the few explicit federal protections trans people had before.

And that leaves LGBTQ people — and especially trans people — worse off than they were before Trump took office.

Advocacy groups argue that federal law should already protect LGBTQ people. Trump disagrees.

Trump’s latest move also flies in the face of the work that advocates have done to obtain federal civil rights protections for LGBTQ people. Specifically, they argue that federal civil rights laws that ban sex discrimination — in the workplace, housing, and schools — do in fact already protect LGBTQ people.

The argument: Discrimination against someone based on their sexual orientation or gender identity is fundamentally rooted in sex-based expectations. For example, if someone discriminates against a gay man, that’s largely based on the expectation that a man should only love or have sex with a woman — a belief built on the idea of what a person of a certain sex should be like. Similarly, if someone discriminates against a trans woman, that’s largely based on the expectation that a person designated male at birth should identify as a man — again, a belief built on the idea of what a person of a certain sex assigned at birth should be like.

This is the argument that the Obama administration embraced in its guidance to public schools. It argued that, under this view, Title IX’s federal ban on sex discrimination also applies to trans people, so schools should respect trans people’s rights, including their right to use the bathroom or locker room that aligns with their gender identity.

Trump, like other conservatives, disagreed. His administration has argued that this was a misinterpretation of federal civil rights law, and that this issue should be left to the states to decide.

“The president has maintained for a long time that this is a states’ rights issue and not one for the federal government,” White House press secretary Sean Spicer said at Wednesday’s press briefing. He later added, “Title IX never talked about this. It was enacted in 1972. There was no discussion of this back then, and to assume certain elements of the law were thought of back then with respect to this would be completely preposterous.”

It’s true that the authors of Title IX may not have had LGBTQ people in mind when they wrote the law. But the law prohibits discrimination based on sex. And whether that was intended to protect LGBTQ people or not, a plain reading of the law and a very basic understanding of how anti-LGBTQ discrimination works indicates LGBTQ people should be protected regardless of the motives behind the statute.

This isn’t just a wild interpretation by LGBTQ advocates; there’s legal precedent for it. Joshua Block, an attorney with the ACLU’s LGBT and HIV Project, cited a 1998 Supreme Court case, Oncale v. Sundowner Offshore Services, Inc., in which the court unanimously agreed that bans on sex discrimination prohibit same-sex sexual harassment. Same-sex sexual harassment was not something that the authors of federal civil rights laws considered, but it’s something, the Supreme Court said, that a plain reading of the law protects.

“Oncale says that’s irrelevant whether [Congress] contemplated it,” Block told me. “That’s not how laws work. This is literal sex discrimination. Whether or not that’s what Congress was focused on doesn’t make it any less a type of discrimination covered by the statute.”

“States’ rights” is a nonsensical reason for allowing discrimination

The counterargument given by Trump and other conservatives is that this issue should be left to the states. Indeed, the letter revoking the guidance for trans students makes this very explicit: “[T]he Departments [of Justice and Education] believe that, in this context, there must be due regard for the primary role of the States and local school districts in establishing educational policy.”

This isn’t how the law works. If federal civil rights law protects LGBTQ people, then LGBTQ people are protected everywhere. Some states and local school districts may not like that, but that’s simply how the law is supposed to work, regardless of what Trump believes or whether he, through letters to public schools, chooses to enforce the law in this way.

In fact, federal civil rights laws were originally passed explicitly because some states might not like providing civil rights protections to certain people. After decades of Jim Crow laws that enabled segregation and other racist policies at the state level, federal lawmakers stepped in to provide some measure of protection in this area after states had so clearly failed.

After decades of anti-LGBTQ discrimination in the workplace, housing, schools, and other settings, most states haven’t passed laws that explicitly protect LGBTQ people. So most states have failed to uphold the most basic American ideal that all people are created equally and should be treated as such. Given this failure, it arguably falls to the federal government to do something — just as it did in the 1960s and ’70s to ban discrimination based on race, skin color, sex, national origin, and religion in federal civil rights law.

Conveniently, a plain reading of the law on sex discrimination already protects LGBTQ people. So there’s an avenue for the Trump administration to overcome its reticence on this issue.

If it doesn’t take this path, the administration is effectively singling out LGBTQ people for discrimination. The Trump administration, after all, is enforcing civil rights law to protect people from racism, sexism, and discrimination based on national origin and religion. But if someone faces discrimination based on sexual orientation or gender identity, as long as your state governments doesn’t intervene, Trump has concluded that it’s fine if you’re on your own and the federal government doesn’t step in to help.

Watch: How should the media cover a White House that isn’t afraid to lie?