Whether the exclusionary rule announced in Mapp v. Ohio applies on collateral review to state convictions that became final before Mapp was decided.
Holding
No. Mapp does not apply retroactively to state convictions that were final before June 19, 1961.
Reasoning
The Court rejected the premise that every new constitutional decision must either apply fully retroactively or only prospectively. A new rule ordinarily governs the case announcing it and cases still pending on direct review, but its application to already-final judgments may depend on the circumstances. The Constitution neither compels nor forbids retroactivity in this setting.
The Court drew on decisions such as Chicot County Drainage District v. Baxter State Bank and Great Northern Railway v. Sunburst Oil, which recognized that an overruled rule may remain an important operative fact for past conduct and final judgments. Retroactivity therefore calls for a practical assessment of the rule's history, purpose, reliance interests, and effect on the administration of justice.
Mapp's principal purpose was deterrence: excluding unlawfully seized evidence was meant to remove incentives for police to disregard the Fourth Amendment. Applying Mapp to completed cases would not deter searches that had already occurred, restore invaded privacy, or otherwise advance that forward-looking purpose.
States had substantially relied on Wolf v. Colorado, which held that the Fourth Amendment applied to the States but did not require state courts to use the federal exclusionary rule. Before Mapp, the Court had repeatedly declined to overrule Wolf, and state courts had entered final convictions in conformity with its then-governing rule.
Full retroactivity would also seriously burden the administration of justice. Courts would have to reconstruct old suppression issues despite lost evidence, unavailable witnesses, and faded memories; and convictions could be disturbed even though the evidence was reliable and the trial's factfinding process was not challenged.
The Court distinguished rules applied retroactively in cases involving coerced confessions, denial of counsel, or barriers to appellate review. Those rules protect the fairness and reliability of the adjudicatory process itself. The Mapp rule instead governs the admissibility of concededly reliable evidence and operates chiefly as a deterrent to official misconduct.