Title VII of the Civil Rights Act of 1964 makes it illegal for employers to discriminate on the basis of a person’s sex. On Monday, the U.S. Supreme Court agreed to address whether gay and transgender workers are covered by the landmark provision, in a trio of cases — two concluding that federal law protects such employees, and one resolving that it doesn’t.

The cases are expected to be decided by the summer of 2020 — that is, in the heat of the presidential campaign. That will make this a political issue, to be sure, but there is significantly more at stake for individual workers.

The Justice Department sowed confusion in 2017 when it went against the stated position of the Equal Employment Opportunity Commission, the federal agency that oversees enforcement of Title VII, and argued before an appeals court that Congress never intended to extend protections to gay workers. That much may be true; the law as written makes no mention of sexual orientation or transgender status. Which could also explain a separate brief in which the department told the Supreme Court that Title VII, as lawmakers wrote it, “does not apply to discrimination against an individual based on his or her gender identity.”

With the passage of time, however, a number of courts, including the Supreme Court, have interpreted the prohibition against sex discrimination generously. Over the past 55 years, thanks to that forward-looking reading of the law, Title VII has addressed harms that Congress never foresaw, such as forbidding sexual harassment and gender stereotyping. Relying on some of those precedents — and the guidance of the E.E.O.C., which in recent years has extended the reach of Title VII to lesbian, gay and transgender employees — modern-day courts have also begun to reconsider their prior decisions on such rights in the workplace, expanding the reach of the law.

As Justice Antonin Scalia wrote in a unanimous 1998 ruling in favor of a male worker who was subject to same-sex harassment, “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.”

So Congress may not have the last word on this matter. What’s more, absent direct action from lawmakers, the Supreme Court would be wise to keep the current progress of the law in place — and not undermine its own prior cases that helped make the American workplace more welcoming and inclusive to all.

FROM AN EDITORIAL IN THE NEW YORK TIMES