By 1917, Great Britain and the other countries fighting the First World War had tremendously advanced their intelligence practices as part of the broader development of warfighting techniques through three years of warfare. The British developed new capabilities such as aerial photography and signal interception to maturity, and further refined classic techniques for intelligence collection, such as prisoner interrogations and document exploitation. Americans observed some of these developments but lacked resources or support to incorporate them into US practice. When the United States entered the war in April 1917, the American army had fallen far behind the other belligerents in strength, organization, and doctrine.
The American army needed assistance to be successful in battle: it had to grow in size just as the British army had done while at the same time modernizing its practices. Some historians have criticized this American effort. Among those receiving blame for American shortcomings is General John J. Pershing, the commander of the American Expeditionary Forces (AEF). According to these historians, Pershing’s rejection of allied trench warfare methods and espousal of his own “open warfare” methods, which were neither clearly defined nor adequately trained, degraded the combat ability of the AEF. While this explanation for the AEF’s shortcomings has merit, the AEF actually drew greatly upon allied experiences in a variety of areas, including artillery, aviation, tanks, and intelligence.
American officers adopted allied intelligence organization, methods, and training into the AEF. Major Dennis E. Nolan, who became the head of AEF intelligence in France, drew upon the information provided in the first allied military missions to the US in April and May 1917, information collected by military attaches, and information he gained from personal observation of the British and French armies in the field to draw up the first American intelligence regulations. These regulations were in many cases word for word the same as British intelligence instructions given to him while at the front. Nolan also largely adopted British intelligence organization for the AEF. Any differences in doctrine and organization from the British model reflected a choice to employ French methods or preexisting American methods. Allied officers trained Americans in intelligence methods even after Pershing began Americanizing the trainers. Finally, the American instructors at the Army Intelligence School (AIS) drew upon the British Intelligence School at Harrow-on-the-Hill, England, when they organized the school, developed curriculum, and later added more course content.
The actions of Nolan and other American officers demonstrate that members of the AEF were receptive to adopting a variety of allied methods into American practice. The AEF’s acceptance of allied, especially British, intelligence primarily appears to have been based on the lack of a comparable American intelligence system at the outbreak of war. Similar adoption of allied methods in aviation, armor, and artillery suggest that too much focus has been placed on Pershing’s opposition to allied trench warfare doctrine in terms of infantry tactics and not enough on the incorporation of allied methods into almost every other functional area of the AEF.