The recent circuit split between the Fifth Circuit and the Eleventh Circuit over collecting cell-site records without a warrant prompts an interesting question about how Fourth Amendment doctrine responds to regional variation. Here’s the question: If two places adopt two different fourth Amendment standards, what law applies when the evidence collection involves both places?

The following hypothetical demonstrates the problem. Imagine that investigators in Arkansas obtain a target’s cell-site records pursuant to a federal court order that falls short of a warrant. Investigators want to show that the target was involved in drug-trafficking crime that started in Arkansas (in the Eighth Circuit), then traveled to Mississippi (in the Fifth Circuit), and then arrived in Alabama (in the Eleventh Circuit). The records show that the phone did so travel, and investigators want to use the records in the criminal case against the target. Under the federal venue statute, the government can charge the crime in any of the districts where the offense occurred. That means the feds can charge the case in the Eighth Circuit, which has not ruled on the legality of obtaining cell-site records without a warrant; the Fifth Circuit, which has held it is legal; or the Eleventh Circuit, which has held that it violates the Fourth Amendment.

Here’s the first part of the question: If the defendant moves to suppress the evidence, is the legality of the government’s conduct based on where the crime is charged or the place where the records relate? Does a court just follow its circuit precedent, or does it defer to the law in the place where the search occurred? I suppose key question is whether a circuit ruling that X is unconstitutional is taken to mean (a) that X is unconstitutional everywhere in the judgement of that circuit or (b) that X is unconstitutional inside the circuit. I would guess that courts would adopt the former view and see their ruling as universal in application, although I can’t cite any cases on that right now.

If I’m right, presumably the government would try to bring the case in the Fifth Circuit given that circuit’s ruling that the practice is constitutional. On the other hand, the defendant might try to preempt that ruling by filing a civil Bivens action in the Eleventh Circuit to get a ruling that the obtaining of records was unconstitutional. But I don’t know how that would go. Would the Eleventh Circuit feel free to rule, or is there an abstention doctrine that would delay a civil ruling? And if the civil court ruled first, would it have any preclusive effect on the criminal case?

Now on to the second part of the question, the remedy stage. Assume that for some reason the case is brought in the Eighth Circuit, and the Eighth Circuit agrees with the Eleventh Circuit that the cell-site collection is unconstitutional. Under Davis v. United States, the exclusionary rule does not apply if the conduct was permitted by “binding appellate precedent.” So what’s the test for “binding appellate precedent” under Davis given that the one act of obtaining records involves conduct in multiple circuits? Is it the precedent in place in the circuit where the order was obtained? Where the litigation is brought? Where the specific parts of the records relate, so some of the data points are suppressed and others admitted?

Perhaps the upshot of these questions is that circuit splits involving the application of law to communications networks should prompt Supreme Court review earlier than other kinds of cases. Maybe splits are a more serious problem. Or maybe there are easy answers to these questions. But if there are easy answers, what are they? Comments very welcome.