In this first week of the new term, the Supreme Court heard two Fourth Amendment cases. The first, Herring v. United States, asked whether evidence obtained based on an erroneous arrest warrant (called in by a police clerk from a neighboring county) should be suppressed. The second, Arizona v. Gant, looked into whether the long‐​standing “Belton” rule that a police officer may search the passenger compartment of an arrested person’s car should be set aside when the the search — typically justified on “officer safety” grounds — occurs after the arrested person is handcuffed and locked in the back of a squad car. The easy legal answers would seem to be yes and yes (though I have qualms about the exclusionary rule — which is fairly unique to America — as a matter of policy), but then it’s hard to craft a readily administrable legal rule that would get you there without creating an equally unjust result in other circumstances. Hard cases, as they say, make bad law.


But my point is not to argue the finer points of Fourth Amendment doctrine. Instead, it is to highlight the difficulty of arguing those points in the rarefied air of the Supreme Court. As the SCOTUSblog analysis of the arguments in the above cases concluded:

The arguments in these cases illustrate the complexity of arguing Fourth Amendment cases before this Court. It is not simply a question of appealing to Justices’ support for, or skepticism of, the exclusionary rule or broad discretion for law enforcement officers. Many of the Justices are also concerned about need for clear, administrable rules, while others simultaneously resist the inflexibility and illogical results a bright‐​line rule inevitably gives rise to. And while some Justices are more than ready to abandon old decisions and doctrines they believe were wrongly adopted or no longer make sense (be it the exclusionary rule or Belton) others feel strongly about the Court’s obligation to adhere to its prior precedent absent strong justification for departure. And to make matters worse, these various considerations often point in different directions and cut across the traditional liberal‐​conservative lines on the Court: Justices Breyer and Alito worry about stare decisis, while Justice Thomas is much less concerned; Justice Kennedy wants a rule that makes pragmatic sense, while Justice Scalia doesn’t care if the rule is nonsensical if it has a historical pedigree; Scalia worries about a vague standard for applying the exclusionary rule, but the Chief Justice not so much. In the end, the cross‐​currents can sometimes give advocates more to work with in crafting arguments that can attract five votes. But at the same time, it sometimes makes the task of holding together a coalition quite complicated.

In short, separating out death penalty cases, it is in criminal law where the justices can be the least predictable.