The school district does not have to reinstate the prom, however. Parents have planned a private prom, instead.
The Clarion-Ledger article linked above noted that "all junior and senior students would be allowed to attend, although it was not clear whether same-sex couples would be allowed to attend together." On other sites, I read that McMillen was not invited to the private prom.
If that is the case, the school board wins, too. They relied on an old southern tactic I described in a piece I did for The Guardian's Comment Is Free:
The prom cancellation is reminiscent of tactics from at least a half-century ago: rather than integrate public pools, parks, and schools, southern municipalities often closed them. Sometimes, in lieu of closure, they turned over such accommodations to private enterprises. In defiance of school integration orders, they opened private schools and segregation academies. Such acts allowed them to continue de facto segregation long after de jure segregation was outlawed.
If you're so inclined, please go check out the whole piece!