My immediate summary account of this Fourth Amendment case obscured the nature of the divide among the justices, so here’s a clearer summary of the ruling:
Justice Souter’s majority opinion (joined in full by the Chief Justice and Justices Scalia, Kennedy, Breyer, and Alito) held that (1) the search of a student’s underwear for drugs violated the Fourth Amendment, but that (2) the school officials who conducted the search were entitled to qualified immunity because the relevant contours of the Fourth Amendment right had not been clearly established. (It left unaddressed the liability of the school district.)
Justices Stevens and Ginsburg dissented on the second point. Justice Thomas dissented on the first point—i.e., he concluded that the search did not violate the Fourth Amendment.
In sum, the vote was 8-1 that the search violated the Fourth Amendment and 7-2 that the school officials were entitled to qualified immunity