It would be hard to overstate the potential impact that Justice Anthony Kennedy’s retirement could have on LGBT equality in the United States.

A more conservative-leaning court could potentially overturn landmark rulings like Obergefell v. Hodges, which legalized same-sex marriage nationwide, but LGBT advocates say that it’s even more crucial to look ahead to the kinds of cases that Kennedy’s replacement is likely to decide in the coming years.

“Trump having the chance to appoint another Justice is really an existential threat,” said Shannon Minter, legal director of the National Center for Lesbian Rights.

Kennedy, who cast the swing vote in major 5-4 LGBT rights cases like Obergefell, could soon be replaced by a Justice with an anti-LGBT track record, judging from lists of possible nominees. That swap would happen at a pivotal moment, just as LGBT legal successes at the district and circuit level were due to be tested by the Supreme Court.

“There are a wide range of questions about LGBT rights that could easily be before the Supreme Court over the next, even, two years,” James Esseks, director of the ACLU’s LGBT and HIV Project told The Daily Beast. “LGBT rights are absolutely something that the country should be concerned about with this nomination.”

One major question headed to the Supreme Court is whether or not LGBT people are indeed protected from employment discrimination under Title VII of the Civil Rights Act, as multiple federal courts—and the Equal Opportunity Employment Commission—have held.

Esseks told The Daily Beast that two to three high-profile cases regarding LGBT employment discrimination could be reviewed by the Supreme Court soon, bringing the long-simmering issue to a boil.

“This would be a huge moment if the Court took these cases,” he said, noting that a ruling against the LGBT community would be a “shock” to the country.

Indeed, surveys like the 2017 Public Research Religion Institute’s 2017 American Values Atlas show that a large majority of Americans—over 70 percent—support laws prohibiting discrimination against LGBT people in the areas of employment, housing, and public accommodations. That includes most Republicans.

Likely replacements for Kennedy, however, are much further to the right, which means we could see rulings that defy public opinion in much the same way that Trump’s executive-level actions on LGBT issues—like the transgender troop ban—have been deeply unpopular.

“If [Kennedy] is replaced by someone who would be a reflexive vote on the other side of those issues, then of course there would be significant reason to fear setbacks and rollback in the courts, along the lines of what we’ve been experiencing with this administration,” Diana Flynn, litigation director for Lambda Legal, told The Daily Beast, adding that we could expect to see the Court to rule on “both new issues and applications of some of the precedents that have already been set.”

Arguably nothing would reverse progress with more brutal efficiency than overturning the 2015 Obergefell precedent. Although LGBT legal advocates believe that outcome is certainly possible, they are more worried about marriage rights being stripped away bit by bit, until Obergefell has been rendered meaningless.

“I don’t think there’s a really significant chance that the Court would reverse any of the landmark rulings about gay people: Lawrence, Romer, or Obergefell,” Minter told The Daily Beast. “I think those likely will remain secure.”

But with the major issue behind the Masterpiece Cakeshop case—namely, the legality of religious-based service refusals—still undecided by the Supreme Court, it’s obvious that anti-LGBT groups still have plenty of space to maneuver against same-sex marriage. A Supreme Court with another Trump pick on it might be sympathetic to arguments from the right that denying service to LGBT people is a “religious freedom” issue.

“They may hold that the Constitution requires some new First Amendment-based exceptions to anti-discrimination laws,” Minter warned.

“ The thing I think we all need to pay attention to—and be worried about—is an agenda that says, ‘Well, fine, the government will give you the marriage license but nobody in the rest of society… has to treat your marriage the same if they don’t want to—and government doesn’t even have to treat your marriage the same.’ ”

From there, it would be easy for anti-LGBT groups to try to turn a same-sex marriage license into a useless piece of paper, arguing that businesses and governments don’t have to take it as seriously as they would a marriage between a man and woman.

“I don’t think it’s very likely that Obergefell itself will be overturned, although it’s possible depending on just how awful the new Justice could be,” said Esseks. “But the thing I think we all need to pay attention to—and be worried about—is an agenda that says, ‘Well, fine, the government will give you the marriage license but nobody in the rest of society … has to treat your marriage the same if they don’t want to—and government doesn’t even have to treat your marriage the same.’”

Esseks pointed specifically to a a 2017 ruling from the Texas Supreme Court, which found, as the Texas Tribune reported, that “the [United States] Supreme Court did not address and resolve” the issue of state-provided benefits for same-sex couples with the 2015 Obergefell decision.

The U.S. Supreme Court decided not to review Houston’s challenge to that Texas Supreme Court ruling last December, effectively opening the door for anti-LGBT groups to argue that same-sex marriage and same-sex marriage benefits are separate issues.

“That would be a way to effectively undermine Obergefell in a very serious way and create serious inequality in the country,” Esseks told The Daily Beast.

Apart from marriage, virtually every other major LGBT issue could end up before the Supreme Court in the near future.

Because the Supreme Court punted the case of transgender teenager Gavin Grimm back down to the Fourth Circuit, the issue of restroom rights for transgender students could end up before the nation’s highest judicial body again—especially because opponents of LGBT equality are now challenging school districts with transgender-inclusive policies, like Boyertown School District in Pennsylvania.

The transgender troop ban, which so far has suffered brutal defeats, could also end up before the Supreme Court soon, depending on how vigorously the Trump administration chooses to defend it.

“I’m still hopeful that the transgender military ban is so extreme, and is one of those rare instances where the government openly singles out a particular group for discrimination that even an extremely conservative court would be given pause by that,” said Minter, but even he acknowledged that the case could be “much more challenging now.”

But LGBT legal groups are far from accepting defeat. Now, says Esseks, is the time to pull out all the stops: “We need to be working using all of the tools that we have to make change.”

“ It would be really the height of hypocrisy and a real danger to the lives of ordinary people generally, including LGBT people, for the Senate to rush this through. ”

The fight, according to Flynn, begins with urging the Senate to take their time with Trump’s eventual nominee—just as they did with Merrick Garland, who was nominated by President Obama in 2016 but never confirmed under the guise of waiting for the presidential election.

“It would be really the height of hypocrisy and a real danger to the lives of ordinary people generally, including LGBT people, for the Senate to rush this through,” Flynn told The Daily Beast.

Even in the event that an anti-LGBT nominee makes it past the Senate and onto the bench, Flynn says that she doesn’t “rule out the possibility that we still would have substantial success in the federal courts”—although the anti-LGBT judicial picks that the Trump administration has been advancing could definitely slow or reverse that success.

LGBT rights groups, Minter admits, have not been as influential as anti-LGBT groups in the area of judicial nominations—and too many LGBT Americans, he believes, have “fallen into the trap [of believing] that progress will just unroll by itself.”

That’s why he hopes that Kennedy’s retirement can act as a “rude wake-up call” for LGBT Americans, in much the same way that Proposition 8’s reversal of marriage equality did for LGBT Californians in 2008.

“We need to re-engage our whole community,” he told The Daily Beast. “Just like many other marginalized groups throughout history who have experienced serious setbacks, there is only one response. And that is to fight even harder.”