Before becoming governor of California, Earl Warren had spent his entire legal career, twenty-two years, in law enforcement. Professor Kamisar maintains that this experience significantly influenced Warren's work as a Supreme Court justice and gave him a unique perspective into police interrogation and other police practices. This article discusses some of Warren's experiences in law enforcement and searches for evidence of that experience in Warren's opinions. For example, when Warren was head of the Alameda County District Attorney's Office, he and his deputies not only relied on confessions in many homicide cases but also themselves interrogated homicide suspects. The seeds of the Miranda v. Arizona opinion may well have been Warren's own keen awareness of the opportunities for coercion and exploitation of confusion in the custodial interrogation setting. Moreover, when district attorney, Warren sought to "professionalize" the police, as well as the prosecutors in his own office. His belief that well-trained law enforcement officials could satisfy the most demanding standards also helps explain his Miranda opinion. Warren's critics viewed his Court's criminal procedure rulings as "handcuffing" the police, but as has been noted by one of Warren's biographers (and former law clerks), G. Edward White, the Chief Justice was convinced that his rulings were not hampering law enforcement, but "ennobling" it.
Kamisar, Yale. "How Earl Warren's Twenty-Two Years in Law Enforcement Affected His Work as Chief Justice." Ohio St. J. Crim. L. 3, no. 1 (2005): 11-32.