In a 5-4 decision released today, the Supreme Court reaffirmed the McNabb-Mallory rule by holding that confessions taken more than six hours after a federal arrest, but before the defendant is presented to a magistrate judge, must generally be suppressed -- even if they are voluntarily given. The Third Circuit, somewhat reluctantly following its prior precedent on the issue, had held that McNabb-Mallory was abrogated by a federal statute (18 U.S.C. 3501) that makes voluntariness the sole criterion for the admissibility of a confession. Today's decision in Corley v. United States, No. 07-10441 (U.S. Apr. 6, 2009), reverses that judgment.
The Court ruled that Section 3501 merely modifies McNabb-Mallory by carving the first six hours after arrest from its ambit. Within six hours of arrest, voluntary confessions are admissible in federal court subject to the standard rules of evidence. Pre-presentment confessions taken more than six hours after arrest (or such reasonably longer time as may be necessitated by the logistics of transportation to the magistrate) must be suppressed unless the delay was "necessary" under the McNabb-Mallory case law. "Necessary" delays include such things as the unavailability of a magistrate, but not -- importantly -- delays for purposes of questioning the defendant or investigating crime.
The Court's decision today changes the law in most of the federal circuits, including the Third, in two important ways. First, it reaffirms that McNabb-Mallory is fully in effect beyond six hours of a federal arrest. Second, it clarifies that suppression under McNabb-Mallory is mandatory in cases of unnecessary delay -- most courts that had continued to apply McNabb-Mallory after the enactment of Section 3501 had held that suppression was ultimately at the discretion of the district court.
Historical perspective on McNabb-Mallory is provided here by Lyle Denniston at SCOTUSblog.