The Influence of Ultra on World War II

In the last half decade, intelligence, once a stepchild in World War II history, has assured itself a place among more fully covered aspects of the conflict. A flood of new information and insights was set off by revelations on the ULTRA secret initiated by Gustave Bertrand and F. W. Winterbotham. The cloud of mystery once dispelled, the door was open to further disclosures on ULTRA itself and the unique role claimed for it in influencing the course of the war and, conceivably, its final outcome. With so much brought to the light of day, the remaining aspects of the clandestine sides of the conflict scarcely seemed worth the trouble of keeping them in obscurity. British Secret Service files, which remained closed in the late 60's when the reduction of the traditional waiting period on the release of public records to 30 years offered so many windfalls to World War II scholars, have become increasingly accessible. This essay will assume a broad familiarity with the epic tale of how Polish, French, and British scientists and cryptologists unraveled the mysteries of the German Enigma machine and, eventually, of most of the codes in which its messages were transmitted. A similar acquaintance is assumed for how ULTRA came to be the central element in first British and then Anglo-American intelligence gathering and appraisal and for innumerable operational decisions. What will be attempted here is a rather far-reaching and risk-taking assessment of the part ULTRA played in the war's Western theaters. Factors which underlined or detracted from its impact on events, estimates of its influence on strategy, and evaluation of its contribution to the outcome of the war will be reviewed. Published in Parameters: Journal of the U.S. Army War College, v8 n4 p2-15, 1978.