In Tuesday's decision in Arizona v. Gant, the Supreme Court limited the search incident to arrest power as follows:

[W]e hold that [New York v.] Belton does not authorize a vehicle search incident to a recent occupant's arrest after the arrestee has been secured and cannot access the interior of the vehicle. Consistent with the holding in Thornton v. United States, 541 U. S. 615 (2004) , and following the suggestion in Justice Scalia's opinion concurring in the judgment in that case, id., at 632, we also conclude that circumstances unique to the automobile context justify a search incident to arrest when it is reasonable to believe that evidence of the offense of arrest might be found in the vehicle.

  I wonder, do the "circumstances unique to the automobile context" justify a search of a car's trunk, not just the passenger compartment?

  The question is interesting and potentially important because the scope of search incident to arrest under New York v. Belton is limited to a search of the passenger compartment of a car. Belton stated its holding as follows: "we hold that when a policeman has made a lawful custodial arrest of the occupant of an automobile, he may, as a contemporaneous incident of that arrest, search the passenger compartment of that automobile." In plain english, Belton allows a search of the interior but not the trunk.

  Gant plainly limits the reachable area aspect of Belton, briging it closer to Chimel, such that the passenger compartment can be searched only when he can actually access the passenger compartment. But does the new exception allowing searches "when it is reasonable to believe that evidence of the offense of arrest might be found in the vehicle" apply beyond the passenger compartment of the car?

  Here's an example of facts that will raise the question. The police pull over a driver and arrest him. They develop a reasonable belief that there is evidence of the crime in the trunk of the car (perhaps the driver keeps looking nervously at the trunk area). However, the police do not quite have probable cause that there is evidence in the car. The police search the trunk and find the evidence. When charges are brought, the defendant moves to suppress the evidence seized from the trunk. Should a court suppress that evidence or not?

  Before Gant, this would have been easy: The evidence should be suppressed. After Gant, however, I think the better answer is that the court should not suppress the evidence, and that this particular aspect of Gant actually expands police power. Nothing in the reasoning of Justice Scalia's concurrence in Thornton (adopted in Gant) seems to be limited to the passenger compartment of the vehicle. Instead, it seems to talk about vehicles generally, and the general interest in collecting evidence there. The formulation of the proposed test adopted in Gant then speaks only of cause to believe the evidence is in the vehicle, and he unique circumstances of cars, not anything specifically about passenger compartments.

  A contrary reading could lead to some strange results. It would be pretty odd if the test were focused on cause to believe the evidence is in the car somewhere, but then allowed only a search of the passenger compartment. If the police had cause to believe the evidence was in the trunk, but they knew there was no relevant evidence in the passenger compartment, the contrary reading would allow them to search only where they knew the evidence wasn't actually located. That would be quite odd. I suppose one way out of this would be to read the new exception as implicitly limited to cause to believe evidence is in the passenger compartment, but that seems hard to square with the actual language used in the opinions. So I think Gant probably does extent beyond passenger compartments.