The Weapons Systems Evaluation Group

Those who work in government and in the private sector supporting government are very familiar with the term “think tank”, a slang expression dating from World War II that denoted an organization filled with “idea men” that sat around desks coming up with better and greater ways for government to operate.  During the World War II era, think tanks were usually linked to finding better ways to win the war.  That think tanks would continue after the war was inevitable given the successes that they met during the war.

The Weapon Systems Evaluation Group (WSEG) was a government think tank organization born in the early days of the newly-created National Military Establishment (NME) that later became the Department of Defense.  The WSEG performed operational research on defense matters from 1948 to 1976.  Very little is publicly known about the WSEG as its records were highly classified and difficult to declassify.  This NDC Blog article will look at the earliest of the WSEG record series maintained at the National Archives at College Park that has been recently reviewed for declassification, and from which documents will be available soon to the public.


According to a 1979 Institute for Defense Analysis (IDA) history prepared for the Joint Chiefs of Staff (JCS) found in the Defense Technical Information Center Library (, the WSEG was an early Defense organization created in the wake of the hallmark National Defense Act of 1947.  The NME staff was small during its two years of existence compared to later manifestations of the Office of the Secretary of Defense (OSD) , with the Secretary (in this case James V. Forrestal) acting primarily as a coordinator between the Armed Services as he had no direct authority over them.  In this decentralized defense organization, the WSEG was intended to serve as an advisory group, analyzing plans and technologies for their effect on national defense.

Initially the WSEG consisted of a joint military-civilian staff.  The military services assigned personnel to the WSEG just as they did to the Joint Staff.  The Federal civilian professionals of the WSEG worked side-by-side with the military staff on specific projects assigned within the WSEG.  The projects were established early in the WSEG’s existence by a directive that came from the Chiefs in September 1949.  From the Joint Staff WSEG history:

1. It is requested that the Weapons Systems Evaluation Group undertake immediately the following project:

a. An evaluation of the results to be expected should strategic air offensive plans be implemented.

(1) Capability of bomber formations to reach assigned aiming points in target system considering means available, probable degree of opposition, training
and logistical requirements and such other factors as are revealed to be pertinent.

(2) Degree of accuracy to be expected in dropping bomb load…

(3) Material damage and loss of life to be expected as a result of bombing, together with consideration of possible psychological effects …

(4) Resultant effect on enemy’s military capabilities or potential.

b. Certain aspects of the problem included under (3) and (4) above have been evaluated by the Harmon Committee …. It is desired, therefore, that the Weapons Systems Evaluation Group devote its attention initially to those phases of the problem listed under (1) and (2).  Should the conclusions resulting from these studies indicate its desirability, the Weapons Systems Evaluation Group is requested to proceed with a review of the findings of the Harmon Committee insofar as they pertain to the subject matter listed under (3) above.

c. Although for the present it is not intended that the scope of the study include the
subject matter listed under (4) above, the Weapons Systems Evaluation Group should keep in mind that at some later date it may be requested to cover this aspect also.
2. As rapidly as staffing capabilities permit, it is requested that the Weapons Systems Evaluation Group undertake the following additional projects, insofar as possible in the priority in which listed:

a. An evaluation of the effectiveness of present and projected antisubmarine warfare
weapons and weapons-systems.

b. An evaluation of the military worth and effectiveness of present and projected
weapons and weapons systems for airborne operations.

c. An evaluation of the effectiveness of present and projected carrier task force
weapons and weapons systems.

d. An evaluation of the military worth and effectiveness of present projected air
defense weapons and weapons systems.

e. An evaluation of the military worth and effectiveness of present and projected
ground force weapons and weapons systems.

3. Prior to consideration of each of the five projects listed in paragraph 2, a detailed outline of the procedures to be followed and the objectives of the evaluation will be forwarded to the Joint Chiefs of Staff for approval.

The first JCS topic, concerning a strategic air offensive, was of the most immediate concern as the Armed Services roles and missions debate had been in full bloom during most of 1949.  President Harry Truman had fired WSEG supporter James Forrestal in March 1949 primarily due to Forrestal’s support of the Navy’s budget position in the procurement of a new class of supercarrier (the planned USS United States). Competing with the Navy was the newborn U.S. Air Force and its monopoly of the means of delivering the only weapon the Truman Administration believed was needed for the defense of the nation–the atomic bomb.  The B-36, a massive aircraft with a maximum bomb load in excess of 40 tons and intercontinental range conceived before the Japanese attack on Pearl Harbor, had been cast by Air Force advocates as the premier atomic delivery system.

This bitter interservice rivalry was exactly the circumstance that drove the formation of WSEG.  At the time of the debate, there was no independent analysis available to the national leadership to point the way to procuring the best weapon systems that supported an agreed national defense strategy.  With Truman and new Secretary of Defense Louis A. Johnson leading the national security team, and with an eye for significantly cutting defense costs, the odds in the B-36 versus United States debate were weighted much in favor of the Air Force heavy bomber.  The point was none too subtly made at Truman’s 1949 inauguration:


B-36A/B Peacekeepers overfly Pennsylvania Avenue during President Harry Truman’s 1949 Inauguration (Photo not in subject record series)

However, the point was also made that a more rational decision-making process for major weapons system procurement had to be found.

Hence the first WSEG product about the planned strategic air offensive against the Soviet Union was a step in that direction.  Known simply as WSEG Report No. 1, the work was quickly completed between the time the Chiefs’ priority list came to the WSEG in September 1949 and January 1950.  Ironically, the intense debate concerning bombers and aircraft carriers became moot six months after the appearance of WSEG Report No. 1.  The outbreak of war on the Korean Peninsula made Truman’s and Johnson’s defense budget reduction plans moot, as cash-strapped Army and Navy commands struggled to respond to North Korea’s surprise aggression against South Korea on 25 June 1950.  Unfortunately, WSEG Report No. 1 is not part of the record series the NDC is processing for declassification; however, its place in history is assured as proof of the need for a WSEG.

What’s in the records?

The WSEG prepared more than reports in the course of its work.  Unfortunately, in the IDA history of the WSEG provided to the JCS, there is no discussion of the variety of products produced by the WSEG.  We have as evidence in the WSEG series being declassified that the WSEG produced reports, staff studies, and  working memoranda, with the bulk of the series devoted to WSEG Staff Studies.  Our WSEG series consists of the following products:

WSEG Report No. 8 (15 July 1952): An Evaluation of Offensive Biological Warfare Weapons Systems Employing Manned Aircraft (Top Secret-Restricted Data), Enclosure A and Appendices A, B, and C to Enclosure A (Top Secret-Restricted Data), Enclosure B and Appendices A, B, C, and D to Enclosure B (Top Secret-Restricted Data) , Enclosure C with Appendices A and B (Top Secret-Restricted Data), Enclosure D with Appendix A (Top Secret-Restricted Data), Appendix B to Enclosure D (Top Secret-declassified), Enclosure E (Top Secret-declassified)

WSEG Staff Study No. 4 (15 August 1951): Operational Experience of Fast Carrier Task Forces in World War II (Confidential-declassified)

WSEG Staff Study No. 7 (20 December 1951): The Continental Air Defense System: An Examination of Some Aspects of the Control and Warning Facilities Available by 1953 (Top Secret-declassified)

WSEG Staff Study No. 8 (1 February 1952): The Potential Contribution to the Soviet War Economy of Areas Possibly Subject to Soviet Domination (Top Secret-declassified)

WSEG Staff Study No. 9 (11 March 1952): The Continental Air Defense System: Estimated Capabilities of Planned Army Anti-aircraft Defenses for the Continental United States as of Mid-1954 Volume I (Top Secret-declassified), Volume II (Secret-declassified)

WSEG Staff Study No. 10 (2 April 1952): A Determination of Measures Required to Maximize the Effectiveness of an Airborne Force When Employed Under the Concepts of Current Emergency War Plans Volume I (Top Secret-declassified), Volume II (Top Secret)

WSEG Staff Study No. 12 (15 June 1954): Capabilities of Atomic Weapons for the Attack of Troop Targets (Top Secret-Restricted Data)

WSEG Staff Study No. 13 (4 February 1955): U.S. Armored Divisions Defense of a Sector Against a Soviet Mechanized Army Volume I (Top Secret-Restricted Data), Volume II (Secret-declassified), Volume III (Secret-declassified)

WSEG Staff Study No. 14 (15 June 1954): The Effects of USSR Preparatory Fires Enclosure A Volume II (Secret-declassified), Estimates of Results of USSR Mechanized Army Assault of the MLR of U.S. Type Corps Enclosure B Volume III (Secret-declassified), Effectiveness of U.S. Armored Division in a Counterattack Role Enclosure C Volume IV (Secret-declassified), U. S. Type Corps in Defense Against a USSR Mechanized Army and Atomic Weapons Effects Enclosure D Volume I (Top Secret-Restricted Data), Definition of a Corps Tactical Situation Enclosure E Volume V (Top Secret-declassified)

WSEG Staff Study No. 15 (15 November 1954): U.S. Type Corps in Defense Against a USSR Rifle Army Volume I (Top Secret-Restricted Data), Volume II (Secret-declassified)

WSEG Staff Study No. 17 (1 December 1954):  Operations of a U.S. Armored Corps Against a Soviet Mechanized and a Soviet Rifle Army Volume I (Top Secret-Restricted Data), Volume II (Secret-declassified), Volume III (Secret)

WSEG Staff Study No. 27 (22 April 1954): The War Supporting Capabilities of the Soviet Bloc from 1 July 1954 Onward (Top Secret-declassified)

WSEG Working Memorandum No. 69 (15 November 1954): A Study of the Capabilities and Effectiveness of Antiaircraft Weapons Systems in the Combat Area Based Upon Analysis of Capabilities to Defend Against Attack by Single Aircraft Flying Straight and Level (Secret-declassified)

As one can see from this document listing, the WSEG was an extremely busy organization in the first few years of the 1950s, as the United States perceived itself surrounded by Communist threats worldwide.

What’s in a WSEG product?

We’ll take a look inside one of the declassified products, WSEG Staff Study No. 9: The Continental Air Defense System: Estimated Capabilities of Planned Army Anti-aircraft Defenses for the Continental United States as of Mid-1954.  Dated 11 March 1952, Staff Study No. 9 is interesting in that it looks at the effectiveness of various antiaircraft systems that were anticipated to be in service two years after the date of the study.  The date of the study is important because of the threat the continental air defense system was anticipated to meet by the middle of 1954.  The Soviet Union had exploded its first nuclear weapon only in August 1949, thus eliminating the four year U.S. monopoly on atomic bombs.  Volume 1 of the Staff Study thus defines the Soviet threat to the continental U.S. in the form of atomic weapons carried by two types of bomber. One bomber was a fairly well-known aircraft, the Tupolev Tu-4 bomber, given the NATO code name of Bull.  The Tu-4 was a reverse-engineered Boeing B-29A bomber, the donor aircraft being four specimens that were interned intact along with one crashed example after forced landings in Soviet territory following 20th Air Force raids on Japan in 1944.

Tu-4 Bull. (Photo not in subject record series)

The second threat aircraft mentioned in the study was the enigmatic Type 31 bomber, about which little was known except the fact that it participated in a 1949 Tushino flyby.  However, the vulnerability of the Type 31 was estimated to be similar to the Tu-4, which, of course, was almost identical to the B-29.  In actuality, the Type 31 was the Tupolev Tu-85, best described as a product improved Tu-4, much enlarged to carry more fuel than the Tu-4 to give it a true intercontinental capability with a significant bomb load.  Ironically, in view of American interest in this aircraft, only two prototype Tu-85s were built, becoming the last piston-engined heavy bombers designed and built by the Soviet Union.  The Tu-85 did lead to another propeller-driven bomber prototype that flew in 1952–the incredibly long-lived Tupolev Tu-95 Bear series, examples of which still serve with the Russian Air Force.

Tu-85 (Photo not in subject record series)

Against the defined threat, Staff Study No. 9 described U.S. Army antiaircraft defenses, estimated to be in mid-1954 the following:

  1. 16 90mm and 120mm antiaircraft gun battalions
  2. 11 Skysweeper battalions
  3. 4 Terrier battalions
  4. 23 Nike battalions
  5. 12 Loki battalions


Of the antiaircraft systems listed in the study, the 90mm and 120mm gun battalions were the survivors of the Army’s vast World War II antiaircraft artillery organization, equipped with gun-laying radars directing the fire of the weapons and using proximity-fuzed projectiles to detonate rounds within lethal distance of their targets.  The Skysweeper was a postwar antiaircraft gun development that took some years to mature.  Standardized as the 75mm antiaircraft gun M51 Skysweeper, the weapon placed gun, automatic loading system, fire control radar and computer on a single gun mount.  The M51 began to enter service only in 1953.  Interestingly, Staff Study No. 9 listed Terrier as an Army antiaircraft weapon system when it was developed as a shipboard Navy antiaircraft missile from its origins in the late 1940s.  Test firings of Terrier only began in 1953.  The Nike battalions mentioned in the study are, in fact, equipped with the Nike Ajax missile, the first fruits of a long term development process that began in 1945.  Nike Ajax first became operational in 1954.  Nike Ajax was related to the Navy’s Terrier as both utilized the same booster stage.  Loki was an interesting low altitude antiaircraft weapon based upon a World War II German antiaircraft system called Taifun.  The Loki system placed multiple small two-stage rockets in a disposable box, with the second stage being an unpowered dart with a warhead and fuze.  Loki depended on a central fire control system to aim and fire the box of rockets at approaching targets.  Unfortunately, the Loki program ran into rocket production quality control and fire control development problems and was ignominiously cancelled in November 1955.

Nike Ajax site SF-91, ca. 1958, Angel Island, San Francisco Bay (Photo not in subject record series)

Volume I of the study laid out the positioning of these various antiaircraft systems around probable target locations nationwide with the types of defenses scheduled to be in place as of mid-1954.  Only 15 locations around the country were programmed to be defended by guided missile systems (both Nike Ajax and Terrier), while another 10 locations had guns and/or Loki for defense.  The volume also contained known intelligence information, rules of engagement, the effect of  countermeasures, and possible improvements to the systems or tactics mentioned in the volume.

Volume II did the heavy lifting with regard to the math and statistics of the efficiencies of the various systems examined.  The volume has 149 legal pages full of tables, graphs, equations, and analysis.  The end result were tables (in the case of Nike Ajax) that indicated the expected fraction of aircraft shot down in attacking area defended by Nike battalions.

The summary of all this analysis was not hopeful to national leaders in the closing days of the Truman Administration.  If the Soviets managed to fly a single bomber at high or medium altitude against any of the cities protected by guided missiles, the defenses had an 80% chance of downing the attacker before bomb release.  For the cities protected only by guns or Loki, there was little chance of downing a high altitude bomber and only a 10-50 percent chance of destroying a medium altitude bomber.  If an attacker came at low level, those localities defended by Nike Ajax or Terrier had a 10% chance of bagging the attacking bomber, while the gun and Loki defended areas would do much better; however, the summary noted that the Soviets would most likely not attack those locations at low level.  If multiple attackers penetrated the same targets, defensive effectiveness would be reduced by factors ranging from 2 to 10, dramatically highlighting the expected ineffectiveness of 1954 air defenses against more than one bomber per target.

Volume I noted that a way to vastly improve defensive arrangements was through the implementaton of what would later be known as an integrated air defense system (IADS).  There needed to be improvements in the speed and handling of communications, data, and decision making for which the technology did not exist at the time of the publication of Staff Study No. 9.  The authors could only hope that the improvements would make a big difference in the effectiveness of the proposed defenses. In fact it took another seven years after the 1952 study was completed to bring the idealized system into service.  Known as the Semi Automatic Ground Environment (SAGE), the system tied together radars, command centers, computers, interceptor aircraft, and surface to air missiles to provide a defense against Soviet bombers


The WSEG products are outstanding examples of think tank work.  Tasked by senior military and civilian officials to analyze and report on specific military scenarios involving the latest military technology, the WSEG staff had to use non-automated calculating tools and statistical methodology to come up with their voluminous analyses.  All this very labor-intensive work was conducted under the condition of extreme stress caused by the precarious international situation of the early 1950s.  One can easily envision lights burning late into the night at the Pentagon as dedicated military members and government employees together worked to keep the national leadership best informed about the dangerous world in which they all lived.





16 thoughts on “The Weapons Systems Evaluation Group

  1. The air defense inefficiency identified in the WSEG report (the “kill probability”) was addressed by adding nuclear warheads to deployed Nike missiles. This increased the lethal blast zone of each missile and obviated the need for a direct (or near direct) hit on the aerial target.

  2. Will the declassified WSEG reports be digitized and made available in the online catalog? From which Record Group(s) were these reports pulled? RG330.2.1 and 330.11.4?

    1. We have not sought a digitization project for these records as NARA’s digitization resources are limited, and we have to be sure there is an audience out there for these records. In light of comments on this post and heard/read elsewhere, we will seek to have these records digitized, although I cannot say when that will happen until we have established a formal NARA digitization project. Once that happens, I will be able to update digitization status on this blog.

      These records come from RG 330, Records of the Office of the Secretary of Defense. The numbers you cite come from the NARA Guide to Federal Records; however, those numbers bear no semblance to the actual designation of the record series, which is RG 330 Entry UD 54B.

    1. Unfortunately the NDC does not have the resources to scan most of the series we declassify in order to make them available online. These records are physically available to the public in the Research Room of the National Archives College Park facility.

      1. Thanks for the update. Are you saying that the WSEG reports, staff studies, and memoranda cited in your March 7, 2018 blog posting have now been fully declassified and are now available for inspection in the unclassified NARA College Park research room?

        1. The reports that are indicated in the article as declassified are publicly available. A number of volumes do still retain their classifications and would not be publicly available.

    1. Unfortunately we do not have the resources to make digitally available most of the series we declassify. However, these records are physically available to the public in the Textual Research Room of the National Archives College Park facility.

Leave a Reply