When Florida v. Jardines, the case where an officer approached a house with a drug-sniffing dog, first came down, Orin Kerr and others noted that the Supreme Court majority never once used the word "trespass." The Jardines concurrence and dissent used the word, and the author of Jardines, Justice Scalia, had used "trespass" repeatedly in United States v. Jones from last term. So why doesn't he use the word in Jardines? Because there really is no trespass test? Because he has new clerks? Just a coincidence?
A law student at NYU named Bradley Pollina offers this theory: the Supreme Court was unwilling to reverse Florida's interpretation of its own common law. Particularly elucidating, I thought, was Pollina's reference to page 59 of the transcript of the oral argument where Justice Alito asked defense counsel why they should not simply take Florida's word for the fact that no trespass had occured.
This may help explain Justice Scalia's majority opinion, but it also creates a new puzzle. What do we make now of Justice Alito's dissent? Recall Justice Alito's admonition in Jones that, "under the Court's [trespass] theory, the coverage of the Fourth Amendment may vary from State to State." Seems as though Jardines is case in point, no? We also know from the transcript that Justice Alito is aware of Florida's characterization. And yet in Jardines, again dissenting, Justice Alito is happy to substitute his own views about trespass over that of the state: "As I understand the law of trespass and the scope of the implied license, a visitor who adheres to these limitations is not necessarily required to ring the doorbell, knock on the door, or attempt to speak with an occupant."