12 Feb 81




SE – 10
Published 15 September 1951


12 Feb 81

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JULY 1952

Published 15 September 1951

The intelligence organizations of the Departments of State, the Army, the Navy, the Air Force, and the Joint Staff participated with the Central Intelligence Agency in producing the section of this estimate covering Direct Military Attack (paragraphs 1-12). The section on Clandestine Attack with Weapons of Mass Destruction (paragraphs 13-33) is based on NIE-31, published 4 September 1951. The section on Subversive Operations, Sabotage, and Civil Disturbances (paragraphs 34-44) was prepared by and has the approval of the Interdepartmental Intelligence Conference.

The members of the Intelligence Advisory Committee concurred in this estimate on 10 September 1951.


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JULY 1952


To estimate Soviet capabilities for weakening, disrupting or destroying the war potential of the United States by a surprise attack against the Continental United States before July 1952.


For the purpose of this estimate it is assumed that:

a. A Soviet surprise attack on the US would be designed to cause the maximum possible reduction in the capability of the US to wage offensive war.
b. The scale and nature of the Soviet effort against the US would not be significantly affected by possible simultaneous Soviet military campaigns in other areas.
c. The USSR would not avoid employing any weapon and tactic because of US capabilities for retaliation in kind.


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Air Attack

1. Atomic bombardment with long-range aircraft is the most effective among the various types of potential surprise air operations against the US within Soviet capabilities during the period considered in this estimate.

2. Other possible types of surprise air attack, such as conventional bombing with high explosives, guided missiles launched from Soviet-controlled territory and the employment of free balloons will not constitute a serious threat during the period of this estimate. Although chemical and biological weapons might be delivered by long-range aircraft, these weapons are better suited to clandestine or sabotage attack. It is considered unlikely that the USSR will possess a hydrogen bomb during the period of this estimate.

Long Range Bombardment

3. The TU-4 is the only Soviet bomber in operational use known to be capable of reaching the US with an atomic bomb from present Soviet bases. Considering present estimates of production and present TO & E strength of about 600-700 TU-4 type aircraft, it is estimated that approximately 1,000 TU-4's will be in units by mid-1952. Although the Soviets have displayed a new bomber, little is known about this aircraft, and it is unlikely that it will appear in operational numbers by mid-1952.

Range of Missions

4. It is believed that operations of Soviet Long Range Aviation would include night and bad weather missions. The following long-range operations could probably be carried out with TU-4 aircraft carrying a bomb load of 10,000 pounds:

a. One-way missions, from potential staging bases in northeast Siberia and from bases in the Murmansk and Baltic areas, could reach any important target in the US. There is no evidence that the Soviets have in fact developed aerial refueling techniques. However, one aerial refueling would extend the range of a one-way mission and enable Soviet planes to reach any important target in the US even from interior launching bases.
b. Two-way missions from Velkal (in Eastern Siberia) could be carried out against the small segment of the US northwest of Seattle. One aerial refueling would extend this radius to include an arc passing through Los Angeles, Denver, and Minneapolis. Two aerial re-fuelings would extend this radius to include an arc running from Galveston to Cape May.

Combat Crew Proficiency

5. Soviet Long Range Aviation has no background of combat experience such as that acquired by the UK and the US strategic air forces during World War II. An intensive training program to overcome weaknesses in long-range navigation, instrument and high altitude flying, and electronics techniques has been under way for some time. Soviet crews could be assisted by planted navigational aids and, if they were successful in gaining tactical surprise, could use US radio and other navigational aids to facilitate navigation, target location, and bomb aiming. Although it is estimated that Soviet blind bombing equipment and all-weather flying capabilities are not up to US standards, it is believed that Soviet combat crew proficiency and equipment performance are such as to permit an attempt by the USSR to carry out strategic air attacks against the US.

Atomic Attack

6. The limiting factor in the scale of atomic attack would be the stockpile of bombs available to the USSR for use against the US. The atomic stockpile for 1951 and 1952 has been estimated as follows:

Mid-1951        45
Mid-1952        100

The above stockpile figures must be considered as uncertain for the following reasons:

(1) The number and/or size of the production facilities postulated in this estimate may be incorrect. The minimum program, which is not inconsistent with the information available, would provide a stockpile of about one-half the number of weapons (shown in the table). On the other hand, from the information available at the present time, the possibility that additional or expanded production facilities will be constructed during the period under consideration cannot be precluded.
(2) The type of weapon postulated for calculating the stockpile figures may be incorrect. It is possible by changing the weapon design to substantially increase or decrease the number of weapons in the stockpile, given a certain quantity of fissionable material. Such changes, however, alter the kilotonnage yield of the individual weapons accordingly.

Atomic weapons available to the USSR during the period of this estimate can be expected to develop from 30 to 70 kilotons TNT explosive power. Their weight would probably be between two and five tons; diameter three to five feet; and length four and a half to seven and a half feet (if a non-ballistic case is used, the length is the same as the diameter). The possession of aircraft, trained crews, and base facilities would permit an attempt by the USSR to deliver against the US the full stockpile of atomic bombs that will be available in the period covered by this estimate.

Airborne and Amphibious Attack

7. The USSR will not be capable of launching an invasion of the US by mid-1952. However, during the period of this estimate the USSR will have limited airborne and even more limited amphibious capabilities for attack against the US.

8. It is estimated that the USSR would be capable of seizing selected areas, including airfields, in western Alaska and the Aleutians by amphibious, airborne, or combined airborne-amphibious operations. Approximately 4,000 airborne and 6,000 seaborne forces might be employed in initial attacks.

9. Because of the problems of resupply, the distances involved, the deficiencies of the Soviet surface fleet, and the lack of adequate routes leading out from probable objective areas, large-scale Soviet amphibious and/or airborne operations against the Alaska Peninsula, Fairbanks-Anchorage area or eastern Alaska are believed impracticable. However, the seizure and retention of areas in western Alaska, specifically of the Seward Peninsula or adjoining areas or parts of the Aleutian Islands is within Soviet capabilities. It is also within Soviet capabilities to execute harassing raids, employing surface lift, airlift, or submarines against Alaska.

10. Airborne operations against the US, although considered unlikely, could take the form of attacks by specially trained assault and sabotage teams against important and difficult bombing targets.

Naval Attack

Surface Fleet

11. During the period under consideration, the capability of the Soviet surface fleet and merchant marine for weakening, disrupting, or destroying the war potential of the US by surprise attack against the continental US will remain very limited.

a. The Soviet coastal warfare force of minor combatant vessels, while numerically large, is entirely unsuited for a surprise transoceanic attack.
b. Although the heavier Soviet surface forces are being strengthened at an appreciable rate in the form of new long-range cruisers and destroyers, they lack the requisite strength and vital carrier-borne air striking power and support for any large-scale transoceanic surprise attack. The USSR will be totally lacking in aircraft carriers during this period.
c. The present character of the Soviet Merchant Marine, a heterogeneous collection of vessels, many obsolescent, and critically lacking in tankers, largely precludes the possibility of its employment in any large-scale transoceanic surprise attack.
d. The USSR presently lacks the advance base facilities or mobile logistic support requisite for an attack against the US. Any attempt to establish advanced bases in the immediate future would eliminate the element of surprise.


12. During the period up to July 1952, the USSR will have an estimated total of 370 submarines, of which 104 will be capable of launching a direct attack against the US. The probable courses of action of Soviet submarines are the following:

a. Attacks on merchant shipping and naval vessels.
b. Offensive minelaying along shipping routes and in the approaches to principal harbors.
c. Landing of saboteurs and agents.
d. Launching of guided missiles and rockets against coastal targets.
e. Small-scale raiding or other diversionary operations.


13. Clandestine attack2 with atomic, chemical and biological weapons3 offers a high potential of effectiveness against a limited number of targets, particularly when employed concurrently with, or just prior to, the initiation of full-scale hostilities.

1/ This section is a summary of NIE-31, which may be consulted for a more detailed discussion of this subject.

2/ For the purpose of this estimate, the term "clandestine attack" does not include either surprise attack by undisguised military forces or the employment of conventional sabotage.

3/ Only atomic, chemical and biological weapons have been discussed, since the state of development of other conceivable weapons of mass destruction is such that their employment during the period of this estimate is considered most unlikely.

Clandestine Atomic Attack

14. The USSR is capable of clandestine delivery of atomic weapons by disguised aircraft, merchant ships and submarines, smuggling, and guided missiles.

Disguised Aircraft

15. Because of its resemblance to the US B-29, the Soviet TU-4 could be disguised with US markings and employed in small numbers for clandestine atomic attacks on high priority targets. The capabilities of TU-4 aircraft discussed in connection with overt air attack (paragraphs 3-5 above) apply to clandestine attack as well.

Merchant Ships

16. The USSR is capable of utilizing merchant ships to deliver atomic weapons into key US harbors. An atomic weapon could be laid as an underwater mine or detonated in the hold of a ship.

17. Laying an atomic weapon as a mine would require encasing the weapon in a watertight container and might also require special laying equipment. The USSR is capable of meeting these requirements as well as providing an accurate time-delay mechanism to permit laying the weapon several days, weeks, or months in advance of D-Day.

18. Detonation of an atomic weapon in the hold of a ship would not involve any special engineering problems.


19. An atomic bomb, including the fissionable material, could be broken down into relatively small components which could be smuggled separately into the US. Unusual handling precautions would not be required and radiation detection would be most improbable. Assembly of the bomb would present certain difficulties but none of an insuperable character.

20. Although it would be theoretically possible to manufacture clandestinely within the US all the components of an atomic weapon with the exception of the fissionable material, it would be difficult to procure and process the necessary material.

21. Under the cover of diplomatic immunity, components for an atomic bomb or, less probably, even an assembled bomb could be consigned to Soviet diplomatic representatives in the US as household effects or supplies without fear of official inspection by US authorities. In addition, no government agency is specifically charged with the responsibility for observing the off-loading, processing, and disposition of such shipments. This method would require the closely coordinated effort of several individuals in the US to acquire the weapon and deliver it to the target area.

22. It is feasible to smuggle an atomic bomb through Customs as a commercial shipment, and many types of imports from the Soviet Satellites could be used as a "cover" for such an act. Furthermore, the number of importing firms in the US is so large that the appearance of a new firm or a change in the imports of an old firm would not automatically arouse the suspicion of the Customs authorities. Theoretically, there are numerous methods by which the USSR could endeavor to circumvent thorough Customs inspection; however, they would involve elaborate arrangements as well as the existence within the US of an efficient organization to establish dummy corporations, subvert employees of bonded carriers, etc. These requirements greatly increase the risk of detection.

23. A more serious threat, well within Soviet capabilities is the smuggling of an atomic bomb, especially if disassembled, from a Soviet port into an isolated section of the US. Such an operation could involve the transfer of a bomb from a Soviet-controlled merchant vessel or submarine to a small boat which would bring it ashore. Here it could be loaded into a truck for assembly and subsequent delivery to the target area.

Guided Missiles

24. It is estimated that the USSR has V-1 type missiles with ranges of at least 100 miles which could be launched from merchant ships or submarines. Such missiles could operate at low altitudes and could have considerably better accuracy than the German operational missiles of World War EL While there is no conclusive evidence that the USSR has an atomic warhead suitable for use in a ship-launched guided missile, the construction of such a warhead is estimated to be within Soviet capabilities.

Clandestine Chemical Warfare Attack

25. The Chemical Warfare (CW) agents most likely to be used for clandestine attack are the G-series nerve gases, primarily because of their extreme high toxicity. The USSR probably has sufficient quantities of the G-series nerve gases (GA and GB) for fairly extensive clandestine attacks.

26. Clandestine nerve gas attack is well suited for employment against personnel in key installations when the objective is immediate incapacitation of a high percentage of the personnel. Nerve gas could be released within a building by means of an aerosol bomb similar to those used for insecticides and equipped with a time mechanism. It would also be feasible to attack buildings by spraying nerve gases in the vicinity.

27. The USSR could attempt to bring nerve gases into the US by any of the methods of smuggling already discussed in connection with clandestine atomic attack, viz., diplomatic immunity, smuggling through Customs, or introduction at a point outside Customs surveillance. In all instances, the successful smuggling of nerve gas or of the complete aerosol dispensers would be considerably easier than the smuggling of atomic weapons. Nerve gas could be easily disguised as one of any number of commercial exports from the Soviet orbit or transmitted in a diplomatic pouch.

Clandestine Biological Warfare Attack

28. It is estimated that the USSR is capable of producing a variety of BW agents in sufficient quantities for extensive clandestine employment against man, animals, and plants.

29. Many types of BW agents are well suited for clandestine attack, and could be employed by the USSR even well in advance of D-Day as part of an over-all plan to impair the military effectiveness of the US. In contrast to clandestine attack with atomic and chemical weapons, clandestine employment of certain BW agents would entail much less risk of identification as enemy action.

a. Very small amounts of these agents would be required initially. Such amounts would be almost impossible to detect when being brought into this country under the cover of diplomatic immunity or through smuggling operations. In addition, it would not be difficult to have some BW agents procured and cultured locally by a trained bacteriologist.
b. The effects of BW agents are not apparent until hours or days after dissemination.
c. The results of many BW agents resemble natural outbreaks of disease, and it would be difficult to connect clandestine employment of such agents with a hostile act.

BW Attack Against Personnel

30. It is likely that the only anti-personnel BW agents which the USSR would employ prior to D-Day would be those causing diseases common to the US, since the outbreak of an unusual disease would probably arouse suspicion as to its source. The statistics of the Public Health Service on the incidence of various diseases in the US are made public and undoubtedly are known to the USSR.

31. In clandestine attack, it probably would not be feasible to build up sufficient concentrations of BW agents to produce large numbers of casualties in urban areas. However, BW agents could be employed clandestinely to incapacitate key individuals and personnel in vital installations. Dissemination of some airborne BW agents within a building probably would cause casualties among a large portion of the personnel. Similar results probably could be obtained from agents disseminated outside of a building and carried into the building by air currents soon after dissemination.

BW Attack Against Livestock

32. In a clandestine attack against animals, foot and mouth disease constitutes the most serious threat to this country. The disease is highly contagious, and there is a relatively long period during which an animal with this disease is capable of infecting other animals before the symptoms become apparent to anyone but an expert. Individual herds could easily be attacked, but more widespread dissemination could be initiated by infecting animals in "feeder" stockyards. Widespread outbreaks of disease could also be brought about by contaminating the anti-toxins, vaccines, and other biologicals manufactured in the US for the inoculation of animals.

BW Attack Against Crops

33. It is estimated that the USSR might possibly employ some form of cereal rust in a clandestine BW attack against US crops. However, such attack is unlikely because of the uncertainty that this disease would spread over a wide area.

It is considered that attacks with other BW agents such as blights, insects, and chemical growth regulators would be impracticable.


1/ The following estimate has been made by the Interdepartmental Intelligence Conference composed of the Directors of the Federal Bureau of Investigation; G-2, Army; Office of Naval Intelligence; and Office of Special Investigation, Air Force.

Groups and Individuals Available for Soviet Subversive Purposes

34. To aid in its attempts to disrupt and frustrate our defensive and counter-offensive efforts in the circumstances of a surprise attack, the USSR has a very formidable ally within our own camp: the Communist Party, USA. The members of that organization, now estimated at 37,000, by virtue of their total devotion to the principles of Marxism-Leninism and to the Soviet "fatherland," are committed to defend the USSR "unswervingly," with all means at their disposal and at any price.

35. Other potential sources upon which the USSR may draw (or from which it may obtain spontaneous aid) are Communist sympathizers, Communist front organizations, some Trotskyites, anti-U S nationalistic groups, and persons otherwise disaffected. Additional potential sources of manpower for aid in subversive purposes are members of Soviet and Satellite diplomatic, consular, commercial, industrial, press, academic and "cultural" establishments and missions, and UN personnel.

36. Although the Communist Party, USA is well known for its highly-developed "monolithic" organizational apparatus, and for its Bolshevik "iron discipline," the recent arrests of top leaders, and the forced hiding of others, have unquestionably caused some disruption in the previously smooth-running Party machine. Further arrests may be expected to cause additional damage to that apparatus and to its subversive potential. However, while it is realized that such action limits that potential, it still remains a threat with which to reckon.

Communist Organizational Tactics in the Present Period

37. The Communist Party, USA has always conducted some of its activities on an underground basis, but since 1947, that basis has been enlarged considerably through the taking of elaborate "security measures" designed to provide additional cover for its activities. Now, since the indictment of the National Board members ( 17 July 1948), and especially since the Supreme Court decision ( 4 June 1951) upholding the conviction of the 11 National Board members, the Party has gone even farther underground. A Soviet surprise attack would surely complete the "descent."

38. Nevertheless, it should be borne in mind that Communists have no desire to go (or remain) wholly underground, except as a last resort; they find such a condition stifling and stagnating. They deem continued contact with "the masses" to be essential even in the face of what they call "a reactionary drive to destroy our Party." Their Leninist principles call for an orderly retreat to regroup their forces for a later offensive. They are mindful of what their Soviet masters declare to be "the most important rule of Bolshevik tactics in periods of retreat, namely, to combine illegal with legal work within the various legally existing workers' societies and unions. . ." Thus, their organizational and tactical principles proper to this situation call for a combination of:

a. underground ("illegal") operation, to preserve the Party from destruction, and
b. aboveground ("legal") activity, carried on through fronts and infiltrated organizations and institutions of all types, with a view to endeavoring to influence "the masses" along Communist lines.

39. Accordingly, it may be expected that in the future -- prior to a surprise attack and also in the event one takes place --Communist activity will be directed toward more than mere self-preservation. The Party will continue to attempt to carry out its general task of intensifying the class struggle during this, the "eve of the proletarian revolution." Furthermore, these attempts to accomplish Communist purposes may be more difficult to detect and to frustrate than in the past, because of their increased subtlety and heavier disguise. The wire from the charge to the detonator will be longer, more tenuous, and more deeply buried than before. . .

Communist Action to be Anticipated in Event of Soviet Surprise Attack

40. In the event of a surprise attack, the Communist Apparatus may be expected to make coordinated attempts immediately to destroy:

a. our will to resist, and
b. our means of resisting.

41. Psychological warfare directed toward the destruction of our will to resist (or toward causing fatal hesitation or confusion in repelling the attack and launching the counter-offensive) might take the form of widespread circulation (effected, e.g., through newspapers with "forged" mastheads and titles, broadcasts over seized radio stations, etc.) of false reports and rumors concerning: the strength and initial successes of the enemy; the destruction and/or capture of important cities; the slaughter of millions of military and civilian citizens by means of both powerful and insidious weapons; the surrender of important units of our Armed Forces; the existence of total confusion among our military and Government leaders; and the unmasking (forced or spontaneous) of Communists in high military and Government posts. Such efforts, if successful, might cause seriously disruptive civil disturbances, such as race riots, a revolutionary situation on the home front, and a lowering of military and civilian morale.

42. To destroy our means of resisting the attack, Communists may be expected to attempt the sabotage of our vital installations and industries. Our highly complex mode of production, with its heavily interdependent operations, offers many opportunities for causing the partial and temporary paralysis of the whole. The long-standing Communist "concentration policy" -- the recruitment (and placement) of members in basic and key industries, particularly "the heavy industries and those of a war character"--has contributed to Communist capabilities with respect to sabotage. Not all Communist sabotage attempts will be directed, of course, toward open, physical destruction. They are well aware that serious damage can be effected over a long period by fomenting labor disputes over real or alleged grievances, and by carrying out a slow-down maneuver under the guise of a fight against "speed-up." (Communist Party members are now being instructed that although it is desirable that they support by agitation the grievances of workers in industrial plants, the members themselves must be kept in the background in such agitation.)

43. Counter-acting the Communist threat, the campaign waged by many major labor unions to expel Communists from their ranks has contributed to the limitation of the Party's sabotage potential. In addition, increased public enlightenment concerning the Communist threat to our security has undoubtedly resulted in greater vigilance on the part of American workers with respect to the cunning tactics of their Communist fellow-employees.

Protective Measures

44. Being well aware of the grave threat to our internal security which the Communist Party, USA and related forces constitute, Federal intelligence agencies have taken extensive measures to limit, and if possible, destroy the destructive potential of that Party. The most important of these measures are the following:

a. The arrest and prosecution of top leaders of the Party.
b. An apprehension and detention program based on constant investigation to identify those persons whose activities indicate they are a potential danger to the internal security, and who should be immediately "immobilized" in a time of emergency.
c. Investigation of the character, loyalty, and associations of Atomic Energy Commission applicants and employees, and of all persons having access to restricted AEC data.
d. Facilitating the protection of resources, premises, utilities and industrial facilities essential to support a war-time industrial mobilization program, through furnishing of information to appropriate authorities concerning subversive activities, investigation of individuals having access to highly classified information, investigation of possible sabotage, furnishing of technical advice, and assistance in formulating policies, standards and procedures for protective measures.
e. Development of informants in basic and in vital industries and facilities with a view to identifying those persons who are a potential danger to the security of -those establishments.
f. Constant, vigorous investigation of subversive groups, and of fronts and "covers" under which Communists may seek refuge and from which they may attempt to continue their "legal," aboveground activities.
g. Measures to insure security and loyalty of government employees, military and civilian, including investigations under the Loyalty of Government Employees Program set out in Executive Order 9835.
h. The coordination and free exchange of information among all Federal agencies concerning matters of mutual interest.


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