Concurring Opinions has a hilarious summary of how the members of the Supreme Court came down on United States v. Santos:

Justice Scalia authored the plurality opinion, joined by Justices Souter, Ginsburg, and Thomas – except for Part IV, in which Justice Thomas did not join; Justice Stevens concurred in the outcome reached by the plurality, but not in its reasoning; Justice Alito authored a dissenting opinion joined by Chief Justice Roberts, Justice Kennedy, and Justice Breyer; and Justice Breyer issued a separate dissent joined by no one else.