“Really, nobody’s getting naked,” said the girl, who is identified as Student A in court papers and asked not to be named to protect her privacy. “This fear that trans people exist and should not have the right to exist. That’s the driving force here.”

The school board election is set for Tuesday, only days after lawmakers in North Carolina, mired in a battle of its own, repealed a state law restricting bathroom use in public buildings. In February, after a dispute among his own cabinet officials, President Trump reversed federal protections allowing transgender students to use the bathrooms of their choice, leaving those decisions to state and local authorities. That in turn prompted the Supreme Court not to take what advocates had hoped would be a defining transgender bathroom case.

Student A has been a pioneer in Township High School District 211, which covers five schools in relatively affluent communities northwest of Chicago that have a patchwork of ad hoc policies for transgender students. She filed a complaint with the civil rights office of the federal Department of Education in 2013 that resulted in a 2015 settlement allowing her to use the girls’ locker room at William Fremd High School, in Palatine (and at other schools during school activities). The school had already been quietly allowing her to use the girls’ bathroom.

But that agreement, essentially a contract between the district and the federal government, applies only to one person: Student A. It will expire when she graduates, making the district’s future policy unclear. Waiting in the wings: two transgender boys known as Student B, now in junior high, and Student C, a freshman at another high school, and a transgender girl identified as N.S. who has filed a state discrimination complaint.