For much of the nineteenth century, the U.S. did not allocate many resources to intelligence gathering. Many Americans were wary of espionage, partly because of the disreputable association of espionage with the Pinkerton National Detective Agency, the nation's first private detective and police agency. In the realm of twentieth-century counterintelligence, a variety of government departments responsible for foreign policy initially engaged in discrete espionage operations with little cross-agency coordination. The FBI, formed in 1908, originally served solely as the investigative arm of the Justice Department. For much of its history the FBI investigated political dissidents and criminal cases. In this article, the authors take a look at the contribution of America's intelligence gathering in its passage into war. (Contains 21 notes.)