Before becoming governor of California, Earl Warren spent 22 years in law enforcement: five as a deputy district attorney (1920- 25); thirteen as head of the Alameda County district attorney's office (1925-38); and four as state attorney general (1939-42). My thesis is that Warren's many years in law enforcement significantly affected his work as Chief Justice of the United States.
Kamisar, Yale. "Earl Warren: Law Enforcement Leads to Defendants' Rights." Law Quad. Notes 47, no. 3 (2005): 87-8. (This article is a condensed version of a talk Yale Kamisar gave at a two-day conference, "Earl Warren and the Warren Court: A Fifty Year Retrospect," held at University of California (Berkeley) in 2004.)