Outcome Sensitivity and the Constitutional Law of Criminal Procedure

Iconic criminal procedure doctrines that perform the same function go by different names. When constitutionally disfavored conduct taints a criminal proceeding, courts must determine how much the taint affected an outcome-and whether the damage requires judicial relief. These doctrinal constructs calibrate judicial responses to, among other things, deficient defense lawyering (prejudice), wrongful State suppression (materiality), unlawful policing (attenuation), and an assortment of trial-court mistakes (harmless error). I refer to these constructs, which tightly orbit the constitutional law of criminal procedure, as rules of outcome sensitivity. Formal differences in sensitivity rules remain enduring puzzles subject to only the most superficial inspection. In this Article, I surface the parallel functions that these rules perform, explain why they should be banished from substantive constitutional law, and advance my preferred view of their legal status: as subconstitutional limits on judicial remedies. At stake are basic behavioral incentives for defense lawyers, police, prosecutors, and judges. I proceed in three parts. In Part I, I map the universe of sensitivity rules. They can be internal pieces of substantive constitutional law (like materiality and prejudice elements), or they can be external limits on remedies for completed constitutional wrongs (like harmless error rules). They can also define downstream constitutional errors distinct from upstream constitutional violations (like certain rules against in-court identification). In Part II, I reject internal sensitivity rules, which unwisely transmit mixed signals to criminal justice actors engaged in disfavored conduct. Such rules undermine crucial professional norms, and they degrade constitutional enforcement that takes place outside the criminal process. In Part III, I argue that external sensitivity rules should be conceptualized as subconstitutonal limits on judicial remedies. That status neatly explains why sensitivity rules apply in state court, it avoids standard criticism of federal common law, and it is less doctrinally disruptive than the external alternatives.