Here’s the blunt reality: The U.S. Supreme Court’s rulings on three cases it will hear arguments about on October 8 could have the most profound consequences yet on LGBT people.

Why?

The three cases ask whether an existing federal law that prohibits discrimination in employment “because of sex” applies where discrimination is motivated by an employee’s sexual orientation or transgender status.

The existing law in question is Title VII of the Civil Rights Act of 1964. That law states: “It shall be an unlawful employment practice for an employer [of 15 or more people] to … discriminate against any individual … because of such individual’s race, color, religion, sex, or national origin….”

LGBT legal activists say that discriminating against an employee because his or her spouse or sexual partner is of the same sex constitutes discrimination “because of …sex.” They say discrimination against an employee whose gender identity differs from the sex attributes ascribed to them at birth constitutes discrimination “because of…sex.”

Attorneys on the other side, which includes the Trump administration, say Congress did not intended to include sexual orientation and gender identity under “because of…sex,” and sex discrimination is when “members of one sex are exposed to disadvantageous terms … to which members of the other sex are not exposed.”

Both sides believe an explicit reading of the law favors them.

“If the Court reads the Title VII statute properly – and simply applies the literal words on the page – we will win,” said Jenny Pizer, senior counsel to Lambda Legal which has submitted friend-of-the-court briefs on behalf of the gay and transgender employees in the three cases. “Having the Supreme Court confirm that understanding…will have enormous, powerful deterrent and remedial effects.” And because similar language is used in federal laws covering housing, education, credit, and health care, said Pizer, a win in these Title VII cases “will be tremendous precedents for future litigation in those areas.”

“The stakes for our community could not be higher,” said Jon Davidson, chief counsel to Freedom for All Americans and former national legal director for Lambda Legal. Davidson characterized the three cases before the court as “the most consequential cases for LGBTQ people since the Supreme Court ruled in favor of marriage equality and the most important cases about transgender people ever heard by the high court.”

The Alliance Defending Freedom, a group that has spearheaded numerous lawsuits to diminish equal protection for LGBT people, has been sending out e-mails telling its supporters that the decisions will have enormous consequences, too. ADF says that, if the court allows “sex” to include “gender identity,” the result could “undermine equal opportunities for women and girls” in athletics, force women’s shelters to accept men, and force schools to “open locker rooms, restrooms, and showers to men who claim a female identity.”

Many Supreme Court observers expect the trio of Title VII cases to be the most watched cases of the 2019-20 term, which begins October 7.

So, what are some of the most important things LGBT people need to know about these upcoming cases?

When and how to watch it unfold

The arguments will begin at 10 a.m. ET on Tuesday, October 8, at the U.S. Supreme Court. The first hour will be spent on two cases involving sexual orientation discrimination; the second hour will be spent on transgender discrimination. People who live in the Washington, D.C., area can spend many hours waiting in line and maybe get into the court chambers to see and hear a few minutes (seats reserved for visitors are rotated). The proceedings are not televised, so the next best bet is to read a transcript of the arguments, which will be made available at supremecourt.gov later in the day. And audio recordings are available at the same site later in the week.

The three cases and their basic facts

There are three cases, all involving Title VII.

Two ask whether Title VII covers sexual orientation discrimination. They are Altitude Express v. Zarda, from New York and the Second Circuit U.S. Court of Appeals, and Bostock v. Clayton County, from Georgia and the 11^th Circuit. Arguments in these two cases have been consolidated and will be discussed in the first hour.

Altitude Express v. Zarda began in 2010, when a Long Island skydive company called Altitude Express fired one of its instructors, Daniel Zarda. The company said it fired Zarda over a customer service problem; Zarda said it fired him because he disclosed to a jumper that he was gay. Zarda filed a lawsuit and, though he died in a skydive accident in 2014, his estate carried on the litigation with the help of Lambda Legal. They won at the Second Circuit, but the employer has appealed to the Supreme Court.

Bostock v. Clayton County began in 2013 when the Clayton County Juvenile System in Georgia fired a long-time employee, Gerald Bostock, after he openly acknowledged joining a gay softball team. The county said it fired him for “conduct unbecoming a county employee;” Bostock said it fired him because he is gay. The 11^th Circuit dismissed his lawsuit, noting it had previously ruled sexual orientation is not covered until Title VII. Bostock appealed to the Supreme Court.

The third case, which will be argued in the second hour, involves discrimination based on transgender status:

Harris Funeral v. EEOC originated in 2014 when funeral home director and embalmer Aimee Stephens filed a complaint with the U.S. Equal Employment Opportunity Commission. Stephens said the Harris Funeral home fired her after seven years on the job two weeks after she informed the employer she would be transitioning from male to female. The funeral home said it fired Stephens because Stephens refused to abide by the company’s dress code, requiring that male employees wear a company-furnished men’s business suit. The EEOC found Harris Funeral in violation of Title VII, and the Sixth Circuit agreed. Harris Funeral appealed to the Supreme Court.

The prospects for victory or defeat

To win at case at the Supreme Court, one must have the support of at least five justices. In the past, LGBT people could pretty much rely on getting that majority from the court’s four generally liberal justices (Justices Ruth Bader Ginsburg, Stephen Breyer, Sonia Sotomayor, and Elena Kagan) and the moderate Justice Anthony Kennedy. Kennedy, in fact, became legendary for providing the critical fifth vote –on marriage equality and striking down the Defense of Marriage Act (DOMA). He also led 6 to 3 majorities in striking down sodomy laws and laws seeking to gut non-discrimination ordinances.

But Kennedy retired last year and, with the death of Justice Antonin Scalia, the new court has a solid five-person majority of very conservative justices. The new justices include Brett Kavanaugh, whose answers around LGBT issues during his confirmation hearing were alarmingly evasive to LGBT activists. They also include Neil Gorsuch, who wrote an article criticizing “liberals” for filing lawsuits on “everything from gay marriage to assisted suicide” to achieve their “social agenda.”

Hence, the prospects for victory have diminished in the past year, to say the least.

Precedent favors a pro-LGBT outcome

One thing leaning in favor of the LGBT parties in these cases is precedent –previous Supreme Court rulings—in two cases.

In one case, decided in 1989, the U.S. Supreme Court ruled that discrimination based on sex included discrimination based on gender-based stereotypes. The case was Price Waterhouse v. Hopkins, in which a female employee at the accounting giant Price Waterhouse was rejected for partnership because some the top officials at the firm considered her too masculine. The Supreme Court plurality said the employer’s refusal to promote the woman was “motivated by stereotypical notions about women’s proper deportment” and that it constituted a violation of Title VII unless the employer could prove “by clear and convincing evidence” that it would have refused the promotion regardless of the employee’s gender.

In the second case, decided in 1998, the Supreme Court, led by conservative Justice Antonin Scalia, said Title VII’s prohibition against sex discrimination, including a prohibition against sexual harassment, could be used to protect an employee from sexual harassment by an employee of the same sex. The case was Oncale v. Sundowner.

The caveat: while lower courts must abide by U.S. Supreme Court precedent, the Supreme Court itself does not. The court has famously reversed precedent in cases involving segregation, interracial marriage, and, corporate financing in elections. Most relevant here, of course, is that the Supreme Court, in 2003 Lawrence v. Texas, reversed its 1986 ruling in Bowers v. Hardwick which had upheld state bans on same-sex sexual relations.

Complications and consequences abound

Relatively speaking, the Supreme Court moves slowly and prefers to leave the driving to Congress. It took 17 years for the Supreme Court to acknowledge that Hardwick was “not correct” and strike down sodomy laws with Lawrence. It took 17 years for the court to strike down the federal Defense of Marriage Act after it was enacted. And it took 43 years for the high court to rectify its dismissal of a marriage equality case in 1972 by striking down state bans on same-sex marriage in 2015.

But while this very large and slow-moving judiciary seemed to complete a full turn towards LGBT equality in 2015’s decision in Obergefell v. Hodges, a headwind seemed to develop last year with the Masterpiece Cakeshop decision. The majority sent the case back to Colorado, saying the state’s human rights commission had expressed “hostility” toward the religious beliefs expressed by a wedding cake baker who refused to make a wedding cake for a gay couple. Some LGBT activists felt that gave “dangerous encouragement” to business owners who might want to circumvent laws prohibiting sexual orientation discrimination simply by claiming religious motivation. Similar cases have since multiplied and will, no doubt, be before the Supreme Court soon.

But the consequences of a ruling about Title VII and sexual orientation and transgender status are even greater. Currently, only 21 states and the District of Columbia prohibit both sexual orientation and transgender discrimination in the workplace.

“If we win,” explained Davidson, “all LGBTQ people will be protected no matter where they live.”

A victory would “also be [a] resounding confirmatory statement that anti-LGBTQ discrimination is wrong,” said Pizer.

“It’s impossible to overstate the ameliorative influence of such statements,” she said. “Witness the profound changes in social attitudes post-marriage equality….”

But there’s an equally enormous consequence and message if the LGBT community loses.

“If we lose either the sexual orientation cases or the gender identity/transgender status case,” said Pizer, “the consequences will be intensely dire in multiple ways. There will be a message that it’s perfectly legal to fire or refuse to hire [or] otherwise to abuse LGBTQ people at work.”