How can very long police questioning make a confession unreliable?

Very long police questioning can render a confession unreliable because it subjects suspects to intense psychological pressure, which may coerce them into making incriminating statements regardless of their truthfulness.1

Historically, the U.S. Supreme Court has recognized that prolonged interrogation—even without physical brutality—can violate a defendant's due-process rights. For example, in Ashcraft v. Tennessee (1944), the court suppressed a confession obtained after 36 hours of continuous questioning under bright lights, citing the overwhelming psychological strain. Similarly, in McNabb v. United States (1943), the court nullified convictions based on confessions secured after three days of questioning in the absence of counsel, emphasizing that such delays in arraignment undermine the integrity of the judicial system.1

While modern federal law allows for some flexibility, courts continue to scrutinize confessions from unusually long interrogations. To protect against unreliable or involuntary confessions, the legal system relies on Miranda warnings, better police training, and close judicial oversight of interrogation methods.12