Edward J. Drea

Drea, Edward J. Defending the Driniumor: Covering Force Operations in New Guines, 1944. Combat Studies Institute, U.S. Army Command and General Staff College. Washington, DC: GPO, 1984. [Petersen]


Drea, Edward J. MacArthur's ULTRA: Codebreaking and the War against Japan, 1942-1945. Lawrence, KS: University Press of Kansas, 1992. 1994. [pb]

Surveillant 2.2 says MacArthur's ULTRA is a "well-written, scholarly work ... [and] will become the standard work on the topic." The author uses "sources on both sides of the Pacific and NSA declassified records." For Kruh, FILS 12.1, this is a "fascinating account.... Drea has provided a superb study of ULTRA and its effect on operational planning in MacArthur's Pacific theater. It is certain to be the prime reference work on this subject for years to come." Periscope 19.4 concludes that this work is "detailed and thoroughly researched," and gives it a "highly recommended" rating.

According to Ferris and Handel, I&NS 10.1 (Jan. 1995), "MacArthur's ULTRA possesses greater analytical sophistication and covers more chronological terrain than the best previous accounts of intelligence during the Pacific war.... Drea does not ... forget that intelligence alone could never win a war. On the other hand, he demonstrates that Ultra was the decisive source of intelligence in the Southwest Pacific, one which fundamentally shaped the course of the Pacific war."

Barnhart, I&NS 8.2, comments on Drea's "impressive research, in both Allied and Japanese materials." This is a "significant work for any student of military intelligence.... Hollandia ... was the high point for Ultra.... [It] never again repeated this performance." Drea's "conclusions are conservative, even guarded.... [A] critical factor invariably was whether the general, usually MacArthur, found Ultra's information supporting his preferred options ... [because] preference always won."

To Whitlock, Cryptolog 14.4, "[f]or anyone seeking to acquire a full and balanced appreciation of the role cryptology played in destroying the military power of Japan..., this book is an absolute necessity." Coakley, AHR, Apr. 1993, believes that this work "is a good piece of scholarship that will find an important place in the growing body of literature on ULTRA's role in World War II."

MI 19.3 views MacArthur's ULTRA as the "best historical work ... on the application of intelligence in Army operations." Drea "evaluates the effect ULTRA had on MacArthur's operational planning and decisions during his New Guinea and Philippines campaigns," and finds that "MacArthur's use of ULTRA was inconsistent.... [W]hile he followed his intelligence in some cases, MacArthur ignored it in others, notably the invasion of the Philippines." The author's "cogent and detailed analysis is backed by impressive research.... Combined with clear writing and provocative arguments, balance and accuracy make this book the standard work on the topic."


Drea, Edward J. "Previews of Hell: Intelligence, the Bomb, and the Invasion of Japan." American Intelligence Journal 16, no. 1 (Spring-Summer 1995): 51-57. Reprinted from Military History Quarterly 7, no. 3 (Spring 1995).

After the decision was made by President Truman on 18 June 1945 to proceed with the proposed invasion of Kyushu in November (Operation OLYMPIC), ULTRA intelligence indicated a rapidly increasing Japanese buildup on the island. The focused reinforcement of southern Kyushu -- where the planned landing sites were located -- was particularly ominous. When the use of the two atomic weapons did not produce an immediate Japanese surrender, General Marshall began to consider the use of the remaining bombs as tactical weapons against Kyushu's defenders. Such an action was made unnecessary by Japan's surrender on 10 August, but what if Japan's militarists had insisted on a fight to the bitter end?


Drea, Edward J. "Reading Each Other's Mail: Japanese Communications Intelligence, 1920-1941." Journal of Military History 55, no. 2 (Apr. 1991): 185-205.

[Japan/PreWWII; WWII/FEPac/Japan]

Drea, Edward J. "Tonkin Gulf Reappraisal: 40 Years Later." MHQ: The Quarterly Journal of Military History (Summer 2004). [http://www.historynet.com/mhq/bltonkin/]

"Editor's note:... In the last several years, more information [about the Gulf of Tonkin incident] has been revealed through the declassification of some documents involving sensitive U.S. radio intercepts of North Vietnamese communications. We asked Ed Drea to write an article that would give our readers the flavor of the confusion during some of the most tense hours in U.S. history, when a shooting situation that occurred in one time zone sparked rapid-fire questions, analyses, and decisions in three other time zones."


Drea, Edward J. "Ultra and the American War against Japan: A Note on Sources." Intelligence and National Security 3, no. 1 (Jan. 1988): 195-204.

The sources here are primarily the various Sigint documents of Record Group 457 in the National Archives. Sexton calls this article a "valuable introduction to a key document collection."

[WWII/RefMats & Magic/RefMats][c]

Drea, Edward J. "Ultra Intelligence and General Douglas MacArthur's Leap to Hollandia, January-April 1944." Intelligence and National Security 5, no. 2 (Apr. 1990): 323-349.

This is an excellent article on the operational use of intelligence. Ultra was not responsible for MacArthur's success, but he made use of the knowledge given him by Ultra to plan his operations.


Drea, Edward J. "Were the Japanese Army Codes Secure?" Cryptologia 19, no. 2 (Apr. 1995): 113-136.

The conclusion: "[T]he security of Japanese army codes fluctuated according to time, place, system, and circumstances. So the answer to the question of the title is, 'It depended.'"


Drea, Edward J., and Joseph E. Richard. "New Evidence on Breaking the Japanese Army Codes." Intelligence and National Security 14, no. 1 (Spring 1999): 62-83.

Using documents released by NSA in 1996, the authors conclude that "Japanese cryptologists, content with the system they administered, complacent about the impenetrability of their codes, contemptuous of their enemies, fell into a classic pattern of believing their system was foolproof."


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