Nuclear Weapon Prepositioning as a Threat Strategy*

Stan Erickson
July 2001

Stanley A. EricksonStanley A. Erickson received a Ph.D. in mathematics from the Massachusetts Institute of Technology in 1974 and has worked for Lawrence Livermore National Laboratory since 1977. Initially Dr. Erickson was in the weapons program there. Since the end of the Cold War, he has worked in the nonproliferation program, in the area of nuclear site and transportation security, and on developing counters to nuclear smuggling in the United States and the newly independent states. He is a past chairman of the military section of the Institute for Operations Research and the Management Sciences.

What Is Prepositioning?
     If a midsized nation were contemplating an activity such as taking over a smaller neighbor, suppressing discontent among some groups, or pushing out its boundary line, it would be concerned about international opposition. It might assume that the United States would be the principal opponent or take a leadership role in blocking it. It might therefore seek ways to prevent any serious US response, especially military, to its activities. If the nation is a new nuclear nation, having accomplished nuclear proliferation either covertly or overtly, it might seek ways to use its new capability to promote this end and to deter the United States from taking any action against it. One possible method would be to preposition nuclear weapons at targets inside the United States and then inform the US government that the threat exists and demand that the United States cease calling for or planning any military actions in the region of the new nuclear nation.

     Concisely said, the new nuclear nation would be using nuclear smuggling as a weapons delivery system prior to any conflict, instead of, for example, using ballistic or cruise missiles in the midst of a war. Research and development of nuclear smuggling has no characteristic signatures as ballistic missile testing does, and this delivery capability could be developed covertly. Prepositioning is not the same as nuclear terrorism or state-sponsored nuclear terrorism, but is a military operation conducted by military personnel, using the new nuclear nations full range of military assets, including intelligence, communications, and special operations forces. Terrorism is a difficult problem to deal with, but one advantage that counterterrorist forces have is the terrorist groups lack of resources, including technical expertise, planning ability, communications capability, transport options, and highly trained manpower. This advantage disappears in the prepositioning threat. Discussions of the terrorist threat revolve around a situation involving a single weapon,[1] whereas in prepositioning, the threat is multiple weapons. This also makes prepositioning a more difficult problem than terrorism. Covert delivery, such as by terrorists, but also by small boats or planes, has been mentioned as part of the 1994 US Counter-Proliferation Initiative[2] and in other contextsfor example as a possibility for Iran if Iran should develop nuclear weapons.[3] Covert delivery is akin to prepositioning but differs in the timing and the potential for asymmetric deterrence.

     Comprehensive reviews of the spectrum of homeland defense roles and missions, such as the article by Michael Dobbs[4], do not refer to any analyses specific to this threat. In fact, this threat further complicates the division of responsibilities among the agencies Dobbs lists as involved with homeland security, which may make the analysis and response to the threat more difficult. The 1997 Defense Science Board summer study on transnational threats[5] concluded that the use of weapons of mass destruction by smaller nations military forces is contraindicated by the ability of US military forces to respond with overwhelming attacks, although the board did not explicitly mention or consider the prepositioning threat. The National Defense Panel, in its 1997 prognosis of security considerations in the 21st century,[6] mentioned in passing that a regional power might use organized infiltration forces to deliver weapons of mass destruction but provided no analysis of the prepositioning threat that might incorporate this delivery method.

     To decide whether this threat is realistic and worth time and attention, it is most important to consider whether a new nuclear nation would attempt to employ it. Attention has been givenfor example, in Planning the Unthinkable by Peter Lavoy et al.[7]to country-specific analysis of leadership decision making. This paper attempts to complement that with a normative analysis of how a generic new nuclear nation might evaluate the risks of employing this threat. If the risks to the new nuclear nation are not very significant and cannot be made very significant, we need either to limit our international role to situations where this would not arise, as Ivan Eland[8] recommends in Protecting the Homeland, or to develop means to counter the prepositioning threat.

     Because of the global spread of technology and expertise, along with management capabilities sufficient to achieve a successful nuclear proliferation program, nations with moderate-sized economies will be able to proliferate more and more easily in the future. The timescale for a successful nuclear proliferation program is only about 10 years. In 1964, a Swiss commission estimated that, starting from nothing, they could have a 250-weapon arsenal with three modes of delivery within 15 years.[9] The South African decision to build an enrichment plant was made in 1971, the decision to build nuclear weapons was made in 1974, and the first weapon was ready in 1980.[10] In Economic and Technological Trends Affecting Nonproliferation,[11] I discuss how the timescale for nuclear proliferation may be shortening even more, owing to diffusion of technical knowledge, improvements in enrichment technology, globalization of engineering management, and economic growth.

     As we shall see here, this mode of delivery requires only minor technological advances, easily accomplished by the new nuclear nation; preparing for it would not add any significant time to the new nuclear nations weapon development program. Furthermore, nuclear weapons planned for prepositioning would not need the weaponization development that a warhead for a ballistic missile would. Any device that can detonate can be prepositioned. This means that, without planning, the United States would have only a very short period following the discovery of the new nuclear nations development program in which to analyze the threat, determine effective responses, and allocate funds and resources to design and prepare the response.

Employment of Prepositioning
     During the Cold War, a great deal of complex thought[12],[13] was put into determining what constituted deterrence, principally between the Soviet Union and the United States, or between the Warsaw Pact and NATO. The basic concept was that if side A could maintain enough capability to create a level of damage on side B, even after side B launched a first strike at the nuclear missiles of side A, it would be able to deter side B from ever attempting the attack. The situation in which a nation with a small number of weapons attempts to deter a large nation with a large arsenal has been discussed in connection with missile exchange as the French force du frappe,[14] but this does not immediately translate to the prepositioning threat.

     In abstract, deterrence theory concerns conflicts in which two types of destruction can occur. One type is destruction of the civilian population or the infrastructure of the nation, and the other is destruction of its weapon systems, which include any vulnerable componentsuch as the weapons and delivery systems themselves, the leadership that might launch them (or, in the case of prepositioning, detonate them), or the communications systems that connect the leadership to the delivery systems. For a thorough discussion of a specific instance of deterrence, there must be substantial modeling and analysis to estimate what levels of destruction can be achieved either before or after the other side has conducted a first strike. Calculations involving the United States vs. the USSR have been prepared in great detail, for example by James Constant[15]; John Battilega and Judith Grange[16]; and J. J. Martin.[17] How much is enough? was the catch phrase of these calculations.

     Deterrence theory assumes that rational actors have control over the decision to begin a nuclear attack. We can assume that the United States will be a rational actor and thus that the new nuclear nation can use the theory to determine how many weapons it needs to emplace in order to make its demands nonnegotiable. It is not clear that the leader of a new nuclear nation would be rational and therefore automatically deterred by the ability of the United States to wreak total destruction on his nation,[18] and it is not clear that simple deterrence theory is applicable to the prepositioning threat. Prepositioned weapons in the United States can be detonated on command, and the equivalent to a Cold War counterweapon attackthat is, to search for them and destroy themis a long and uncertain process. Thus, the weapons do not need to be used all at once, and the leadership of the new nuclear nation can detonate a demonstration weapon, either in a remote location to establish credibility or in a city to create nationwide panic in the United States, to make its threat nonnegotiable. The answer to How much is enough? for this situation is different from the answer for a Cold War missile exchange.

     The decision to retaliate is presidential and congressional. If a US city were devastated by a nuclear weapon and there were strong indication that other cities were at risk, panic might ensue, with the population evacuating itself to rural areas. The economy would come to a standstill. The President, in this situation, has the choice (1) to back down and allow the new nuclear nations seizure of territory or other activity to stand, or (2) to retaliate. It goes without saying that the US nuclear arsenal can lay waste to any nation. However, this retaliation may not ensure that the new nuclear nations remaining weapons are not detonated in the United States, even if the US strike is directed at the military command and control network in the new nuclear nation or at its political leadership. Does a President want to risk more cities and thousands or hundreds of thousands of casualties, expose the nation to massive economic losses, and perhaps have the United States slip from its position as the leading power on the planet? Failing to retaliate does not guarantee that no further detonations will occur, nor does it ensure that no further demands will be made.

     This is a very difficult decision, and one that cannot be predicted. No sure-win situations are apparent. It might be possible to evacuate all US cities, conduct a retaliatory strike, and then attempt to find the weapons. However, this search might take months, especially if there are ten or more weapons. The nations food-distribution system might fall apart, essential services could not be provided, and shelter would be almost impossible to provide. There might never be publicly credible assurance that the last weapon has been found. There might be a public demand, expressed in the media, for an immediate replacement of the government or the part of it that was responsible for the lack of preparation and defense. Furthermore, the new nuclear nation might, as a hedge against such a response, also preposition weapons in the capitals of some principal US allies, allowing more options for threats.

Deterrence Calculations
     The equivalent of the Cold War deterrence calculations in this asymmetric situation would center on two questions: How many weapons could a new nuclear nation credibly introduce into the United States, or, for that matter, into a hostage country? and Could the United States eliminate the threat of nuclear detonation on its own territory either before or after a new nuclear nation made demands based on the threat?

     These questions involve the details of the delivery system that brings the weapons into the United States, stores them here, and readies them for detonation. They also involve consideration of auxiliary systems, principally the communication systems that would be used to control the detonations. They might also include the forces emplaced here to support the prepositioning. If the United States can eliminate one of these key components, it may be able to eliminate the threat or buy enough time to find the weapons, if that is possible. These calculations depend on the plans of the new nuclear nation.

Assessing the Risk to a Nation Attempting Prepositioning
     There are several categories of risk. One predominant risk is that the new nuclear nations attempt to preposition weapons will fail, the United States will not be deterred from military action, and, consequently, the new nuclear nation will suffer a crushing military defeat and perhaps an occupation or forced change of government. The other predominant risk is that the deterrence strategy may backfire and the United States may launch a nuclear strike on the new nuclear nations nuclear facilities, military forces, or national infrastructure. Other forms of punishment attack could occur. Lower-level risks, such as embargo, also exist, but this paper considers only the two dominant ones: failure and retaliation.

     Prepositioning failure may occur if the weapons are not successfully emplaced or if they cannot be used. First, there is the risk of interception. If the intended weapons never are successfully transported into the United States but are stopped and captured and attribution to the new nuclear nation can be confidently assured, the United States might retaliate militarily. Based on the amount of successful smuggling into the United States, this capture would likely require intelligence obtained from some source within the new nuclear nation or from personnel in the United States or a transit country involved in the smuggling, although a chance detection is certainly possible and has to be taken into account. If the intelligence were made credible with the capture, attribution would not be in question. However, if the detection is made by other means, especially by a chance encounter, attribution might be difficult under certain circumstances.

     The new nuclear nation could attempt to contain the intelligence risk by using counterintelligence; the confidence that the new nuclear nation has in its counterintelligence forces will likely determine how it assesses the risk of failure. The example of the nuclear proliferation program in Iraq serves as an indication of the difficulty that US or allied forces have in penetrating clandestine nuclear weapons programs. Furthermore, the number of people involved in prepositioning can be kept quite smalla hundred or lessand thus the risk of leaks before delivery is completed can probably be kept small.

     The risk of chance detection and interception can also be kept small by the use of test runs. If capture occurs, the new nuclear nation would want attribution to be as difficult as possible. The US capability in forensics would certainly be called on to examine the weapon and attempt to find clues that indicate the country of origin. This evidence could be disguised to appear to be the product of a different nation, but like the situation with criminal evidence, multiple means can be used to collect the confirming evidence needed for the credible assurance that the attribution is correct. The cost of misattribution is high: the wrong nation receives the retaliation. These competitions between intelligence and counterintelligence and between forensics and counter-forensics, have an unforeseeable outcome. However, both possibilitiesintelligence penetration and chance discoverydo not seem to be uncontrollable by the new nuclear nation.

     Very likely, if the new nuclear nations weapon is captured, retaliation by the United States would be with conventional arms, perhaps by bombing attacks on the new nuclear nations infrastructure. Nuclear retaliation in a situation where the new nuclear nation had never used a weapon would provide opponents of nonproliferation with more arguments to use against it. Even if one nation had proliferated successfully, many others would not have, and the first use of a nuclear weapon by the United States would surely promote the disintegration of the nonproliferation regime. Instead of facing the prospect of a single nation acquiring nuclear capability, which is assuredly a difficult problem, the use of nuclear weapons against the new nuclear nation could lead to multiple instances of new nuclear programs or the dissolution of the Nuclear Non-Proliferation Treaty. While there might be some political calls for nuclear response to an attempt at nuclear delivery (without actual delivery or threats to detonate) the overwhelming motive would be to hold the line on nuclear proliferation and therefore to abdicate any use of nuclear weapons in any situation except counterstrike. If any residual uncertainty exists about the ability of the new nuclear nation to use its nuclear weapons on US forces, retaliation might be restricted to political and economic measures. Thus the new nuclear nation might consider the risk of these consequences to be tolerable.

     Failure of prepositioning could also occur if the weapons are captured inside the United States. However, if the United States is contemplating some military action against the nation, then it must be sure that all the weapons have been discovered. If there are some leftovers, they provide a deterrent to US action. Does the United States have the ability to sweep all its cities and major infrastructure targets in a reasonable time to determine that there are no hidden nuclear weapons?

     There is also the risk of weapon failure, in that the nuclear weapons delivered and secreted within the United States might be duds. Design information for the simplest type of weapons is available, and it is likely that a new nuclear nation would use simple designs at first. The associated risk that the delivery personnel have not assembled the weapon properly, or that the remote detonation receiver is nonfunctional, or that the weapons have been damaged during transport, can also be reduced with training and testing. Similarly, the risk of accidental detonation during delivery can be minimized.

     Given these risks, none seem immediately important enough to prevent a new nuclear nation from attempting prepositioning. Investment by the new nuclear nation in the technologies and procedures needed for counterintelligence, counter-forensics, assured communications, and assurance of no accidental detonation can go a long way toward reducing the risks to the new nuclear nation, as would the tactic of multiple weapons, delivered in several batches or individually and each hidden in a unique fashion.

     The other predominant risk, that the United States will not succumb to the threat and will retaliate after the first detonation, perhaps with nuclear weapons against the new nuclear nation, is also estimatable but not predictable.

     The United States may choose to follow a proportionate response, which has been discussed as a possible US policy.[19] This might translate to a one city for one city, or one dam for one dam retaliation rule. This constitutes a plan for continued detonations if the new nuclear nation chooses to follow it. However, the conduct of the United States in past conflicts has been based on minimizing casualties to military forces. If civilians are at risk, the reluctance toward casualties is likely to be even greater. A new nuclear nation would have to assume that this preference would stay the same, and that the United States, unwilling to risk massive casualties, would not take action until it could establish that it was free from weapons that could be detonated.

Counters to the Prepositioning Threat
     Counters to this threat would include the use of intelligence resources focused on detecting the transition of a nation from Non-Proliferation Treaty adherence to nuclear capability, in which case forcible means of nonproliferation[20] could be used to eliminate the nations nuclear capability before a prepositioning threat became possible. Intelligence assets could also be devoted to assessing the number of weapons in the new nuclear nation, because until the new nuclear nation had weapons well in excess of the number needed for a prepositioning attack, there would be no threat. (It is difficult to imagine that a new nuclear nation would use all its weapons in such a situation, leaving itself with none on its homeland for other purposes.) In general, national and international interdiction efforts counter nuclear smuggling as a delivery means, and strengthening the ability of nations to detect nuclear weapons increases the possibility of detection before the weapons reach their intended ground zero. The emplacement of detection apparatus in as many routes of commerce as possible can reduce the chances that such routes can be used for nuclear smuggling.

     Once a weapon is inside the United States, detection may depend on chance encounters rather than comprehensive search. An aware public can play a useful role in such a situation.[21] Once clues are obtained regarding neighborhoods in which such weapons are located, searching does not pose as much of an overwhelming problem if resources have been prepared and provided. Dealing with a new nuclear nations military forces within the United States is not a problem, even if they are disguised as civilians. However, disabling an armed nuclear weapon that has been booby-trapped is a matter of extreme skill and care, and it needs to be evaluated in great detail and with great effort. With a city at stake, determining the method of booby-trapping and then countering it requires extreme competence and needs study, training, and exercises.

     If it were possible to eliminate the firing signals, then nothing would detonate. If one weapon were found and the booby traps on it were defeated, disassembling it and determining how the signals were received might allow some jamming of the frequency or frequencies used by the receiver.

     At least six steps can be taken to reduce the risk of the nuclear prepositioning threat and to make the chance that it would even be contemplated by a new nuclear nation less likely:

  • Strengthening intelligence in the area of nuclear nonproliferation

  • Making serious efforts to defeat smuggling

  • Carefully improving public awareness

  • Improving search techniques and equipment

  • Developing methods of undoing booby-trapping

  • Building equipment nationwide, on a long-term basis, to decipher and defeat captured communications equipment
     There are undoubtedly other steps that could be taken. Whether the United States has to face a new nuclear nations demands in real time may depend on the degree and speed with which these counters are developed and how persistent we are in maintaining our ability to use them.

Summary and Conclusion
     From the preliminary discussion presented here, the prepositioning threat appears realistic and might be tried under certain circumstances. It requires careful planning to be carried out, but at this time there is no simple, obvious counter to a well-planned prepositioning threat. The risks to the new nuclear nation attempting it, even if the attempt is well planned, are serious; therefore prepositioning would be attempted only if the goal of the new nuclear nation were of great value or importance. But these goals have arisen in the past and may again. Perhaps the worst situation would be for the United States to adopt a mindset of This could never happen, reminiscent of the one that said, The Japanese air force cannot reach Hawaii. Casual estimates of capability are useful but are not sufficient when evaluating the potential for a major homeland attack by a motivated opponent.

     Counters can be developed, improved, and used against such a threat, and several have been mentioned here. More investigation is called for so that prudent decisions can be made about what should be done to ensure that the United States has the best possible chance to cope with such a threat if it should arise.

* This work was performed under the auspices of the US Department of Energy by the University of California, Lawrence Livermore National Laboratory, under contract No. W-7405-Eng-48. The opinions expressed herein are those of the author and do not necessarily represent those of the laboratory, the US Department of Energy, or the US government.

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[1] Richard A. Falkenrath, Robert D. Newman, and Bradley A. Thayer, Americas Achilles Heel: Nuclear, Biological, and Chemical Terrorism and Covert Attack (Cambridge, MA: MIT Press, 1998).

[2] William S. Perry, Proliferation: Threat and Response (Washington, DC: Office of the Secretary of Defense, 2001).

[3] Michael Eisenstadt, Living With a Nuclear Iran? Survival, Vol. 41, No. 3, 1999, p. 124.

[4] Michael Dobbs, Homeland Security: New Challenges for an Old Responsibility, Journal of Homeland Security, Vol. 1, No. 1.

[5] Defense Science Board, The Defense Science Board 1997 Summer Study Task Force on DoD Responses to Transnational Threats (Washington, DC: Department of Defense, October 1997), Vol. 1, Final Report, p. 15.

[6] National Defense Panel, Transforming Defense: National Security in the 21st Century (Arlington, VA: National Defense Panel, December 1997), p. 26.

[7] Peter R. Lavoy, Scott D. Sagan, and James J. Wirtz, Planning the Unthinkable: How New Powers Will Use Nuclear, Biological, and Chemical Weapons (Ithaca, NY: Cornell University Press, 2000).

[8] Ivan Eland, Protecting the Homeland: The Best Defense Is to Give No Offense (Washington, DC: Cato Institute, Cato Policy Analysis No. 306, May 1998).

[9] Carey Sublette, Nuclear Weapon FAQ (Washington, DC: Federation of American Scientists [], February 1999), section 7.4.7.

[10] Ibid., section 7.4.4.

[11] S. A. Erickson, Economic and Technological Trends Affecting Nonproliferation, Nonproliferation Review, Summer 2001 (in press).

[12] E. S. Quade, Principles and Procedures of Systems Analysis, in E. S. Quade and W. I. Boucher, Systems Analysis and Policy Planning: Applications in Defense (Santa Monica, CA: RAND, Report R-439-PR, 1968).

[13] James R. Schlesinger, The Changing Environment for Systems Analysis, in E. S. Quade and W. I. Boucher.

[14] Albert Wohlstetter, Strength, Interest, and New Technologies, in The Writings of Albert Wohlstetter (Santa Monica, RAND, report D(L)-16624-PR, 1968).

[15] James N. Constant, Fundamentals of Strategic Weapons (The Hague, Netherlands: Martinus Nijhoff Publishers, 1981).

[16] John A. Battilega and Judith K. Grange, eds., The Military Applications of Modeling (Wright-Patterson Air Force Base, OH: Air Force Institute of Technology Press, 1984), pp. 237428.

[17] J. J. Martin, Modeling Nuclear Warfare, in Wayne P. Hughes, Jr., ed., Military Modeling (Alexandria, VA: Military Operations Research Society, 1984), p. 95.

[18] Janne E. Nolan, An Elusive Consensus: Nuclear Weapons and American Security After the Cold War (Washington, DC: Brookings Institution Press, 1999), p. 70.

[19] Nolan, p. 80.

[20] Erickson, Economic and Technological Trends (in press).

[21] S. A. Erickson, The Publics Role in Preventing Nuclear Smuggling, Lawrence Livermore National Laboratory report UCRL-JC-138881, November 2000.