One of my favorite quotations (the source of which I have been unable to track down) is "All analogies limp."
That's a problem for the Supreme Court, and not just because both the justices and the lawyers who argue before them are fond of comparing one thing (say, an individual health insurance mandate) to another (a law requiring you to buy broccoli).
Limping analogies play an even more fundamental role in the court's work. The doctrine of precedent, which determines the outcome of cases except when it doesn't, holds that "like cases" are to be decided the same. But one justice's definition of a "likeness" will differ from another's.
On Tuesday, the court heard arguments in a California case raising the issue of whether police should have to obtain a warrant before searching the contents of a smartphone. David Leon Riley was initially pulled over because his car had expired tags. After police found guns in the car, they arrested Riley and searched through what one detective called "lots of stuff" on his Samsung smartphone, including evidence of gang affiliation and a photo showing Riley and another man posing near a car that had been involved in a shooting.
In previous cases the Supreme Court has upheld the warrantless search of objects on the persons of people taken into custody. But that was in the days before smartphones, which can contain a multitude of personal information.
Cue the analogies.
Riley's lawyer, Stanford law professor Jeffrey L. Fisher, compared the contents of the smartphone to "the private papers and the drawers and bureaus and cabinets of somebody's house." If that's the case, Riley wins. The 4th Amendment refers to the "right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures."
Fisher argued that there was a difference between physical items and digital information, which is the limp in Alito's analogy. But all analogies limp, including the one Fisher offered between smartphone data and the cabinets in someone's house. A phone is not a house, and the Supreme Court long has treated physical dwellings with special reverence.
Still, some analogies limp less than others. In this case, the explosion of information contained in smartphones makes them more like cabinets than billfolds, and the justices should rule accordingly.