McNabb-Mallory Rule

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A doctrine of criminal procedure (based on the U.S Supreme Court’s rulings in McNabb v. United States (1943) and Mallory v. United States (1957)) that 1) requires officers to promptly present defendants before a judge or judicial officer after arrest and 2) requires judges to exclude any confessions or evidence produced by police officers during the time period between arrest and the defendant’s initial appearance hearing.

The Purpose of the Rule

The purpose of the McNabb-Mallory rule is to protect defendants from being coerced into self incrimination. During their initial appearance, defendants are notified of their charges, bail, and options for counsel. By requiring authorities to bring a defendant before the magistrate without unnecessary delay, the rule promotes defendants’ and courts’ interests in due process, efficiency, and equity.

The McNabb-Mallory Rule and the Constitution

The McNabb-Mallory rule is not directly based on the Constitution but instead on the United States Supreme Court’s interests in fairness and efficiency. However, it is rarely cited by judges because of the broader protections afforded by the Miranda rule.

Application of the McNabb-Mallory Rule at the Federal and State Level

The McNabb-Mallory rule has been codified into Rule 5(a) of the Federal Rules of Criminal Procedure. Most state penal codes have adopted Rule 5(a)’s mandate that defendants be brought before a magistrate judge without “unnecessary delay” (usually within 48-72 hours of arrest) – with delay measured as the entire duration of custody. If a defendant is brought into court late or is found to have produced confessions while in custody, they may have their suits dismissed on the basis of due process infringement.

The rule is also legislated in 18 § 3501(c); the provision implies that statements made by an arrestee more than six hours after arrest and before the defendant’s presentment to a magistrate judge may be suppressed if the court determines that the delay in presentment was “unreasonable or unnecessary” and that the evidence was involuntarily produced by the defendant.

More Recent Developments – 2009

The U.S Supreme Court’s ruling in Corley v. United States (2009) reaffirmed the rulings in McNabb v. U.S (1943) and Mallory v. U.S (1957). The standard set in Corey requires that a confession be suppressed if (1) it was made prior to the arrestee’s presentment to a magistrate judge; (2) the presentment to a magistrate judge was unreasonably or unnecessarily delayed; and (3) the confession was made more than six hours after the arrest or detention.

The McNabb-Mallory Rule in the Virtual Age

Initial appearances may be conducted via video teleconferencing, with the consent of the defendant.

Relevant terms:




Criminal law

Criminal procedure

Constitutional law

Due Process

Federal criminal code

Fourth Amendment

Fifth Amendment

Initial Appearance


Miranda v. Arizona (1966)

Miranda Warning

Sixth Amendment

Speedy trial

[Last updated in August of 2020 by the Wex Definitions Team]