The Supreme Court’s decision today in the case of Wal-Mart v. Dukes is ostensibly focused on a narrow procedural issue but is in fact the latest installment in a long running debate about equality, in the workplace and beyond.

The procedural issue before the court was whether the sex discrimination claims of one and a half million current and former female Wal-Mart employees can be joined into a single lawsuit against the giant retailer. Under the federal rules of civil procedure, that inquiry turns principally on whether the claims are sufficiently similar. In overturning the lower courts’ certification of the plaintiffs as a single class, the Supreme Court answered no.