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 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 open the door for the justices to settle the issue for the whole nation. The cases are expected to be decided by the summer of 2020 — that is, in the heat of the presidential campaign, when voters will be judging candidates in part on where they stand on gay and transgender rights. 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 filed in October, 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.