At stake is the meaning of “sex” in Title VII of the Civil Rights Act of 1964. The Supreme Court’s ruling will decide whether employers can keep separate showers and locker rooms for men and women, whether women and girls have the right to compete and win at sports and whether shelters for women who have been abused must allow men to sleep alongside them. This is not a “parade of horribles.” These situations have been or are being litigated right now in jurisdictions where governments or officials have added sexual orientation or transgender status to their laws.

For over 50 years, the answers to these questions were clear. But cultural shifts and activists’ attempts to bypass Congress have resulted in a legal clash. Advocates like Gregory Nevins at Lambda Legal now claim that Title VII’s ban on sex discrimination—which gives women an equal place in American life—actually barred LGBT discrimination all along. If that’s right, we’re to believe that, even as LGBT advocates cheered state and local governments for adding sexual orientation and transgender status to their laws, those laws were redundant because the federal government had already extended the same protections decades earlier by using the word “sex” in Title VII.