At the Washington summit in December 1987, the United States and Soviet Union signed the Intermediate-range Nuclear Forces (INF) Treaty, eliminating all their intermediate-range and shorter-range missiles, and instructed their negotiators in Geneva to work toward a reduction of strategic offensive nuclear arms by approximately 50 percent. The two countries also agreed to sweeping new cooperative procedures for verifying treaty compliance. At the same time, however, charges and countercharges of treaty violations have been exchanged, efforts to resolve current issues of compliance at the Standing Consultative Commission have broken down, and the United States has formally abandoned all Strategic Arms Limitation Talks (SALT I and SALT II) limits on strategic offensive forces. The present period is thus characterized both by high hopes for new compromises and by antagonism on a variety of major issues.

No one can say what will emerge from this turbulent atmosphere in the long run. But no matter what happens in the continuing negotiations, it is clear that if lasting improvement in the superpowers’ strategic relations is to be achieved during the next two decades, it must arise from a realistic assessment of contemporary U.S.-Soviet relations and of likely military and political developments.

One necessary element in charting a path toward a more stable relationship is a pragmatic judgment of technological trends and their military implications. These technological realities constitute the constraints or boundary conditions that the United States and the Soviet Union will almost certainly have to cope with in setting defense priorities and in negotiating arms control agreements during the next twenty years.

We begin by summarizing those technical realities and trends that can reasonably be foreseen over the coming two decades. These provide the basis for formulating an approach to increasing both the security of the United States and the stability of the nuclear arms balance with the Soviet Union. This approach incorporates both very specific bilateral agreements and de facto arms control through judicious unilateral decisions about weapons development and deployment. Above all it is designed to point out a pragmatic path for the near-term future.

II

The land-based intercontinental ballistic missile (ICBM) forces of the United States and the Soviet Union are each capable enough to cause apprehension as to their potential for a devastating first-strike counterforce attack against the other superpower’s fixed, land-based targets. A 50-percent reduction, such as may be negotiated in the Strategic Arms Reduction Talks (START), will not change this situation appreciably. In response to this threat, both nations will continue to develop, test and deploy mobile ICBMs, unless limited by strict treaty provisions. As long as mobile missiles are allowed, their total number is not likely to be accurately verifiable. However, if a treaty were to allow only small mobile missiles armed with single warheads, the overall uncertainty about the number of warheads deployed and their leverage in threatening counterforce attacks would be correspondingly reduced.

Both countries will also continue to develop, test and deploy in large numbers submarine-launched ballistic missile warheads with very high accuracy, comparable to that of the best ICBM warheads, which will be capable of delivering a prompt counterforce attack against hard targets such as missile silos, command posts and communications centers. Unless otherwise constrained, the numbers and accuracy of the U.S. SLBM force, and possibly of the Soviet SLBM force, will come to cause the same apprehension that ICBMs now do. However, operational difficulties (such as launch coordination) rather than technical considerations will continue to make a devastating counterforce attack from SLBMs less credible than one from ICBMs.

Both technological and operational considerations will prevent gains in acoustical detection capabilities from threatening the security of deployed strategic submarine forces. Research in nonacoustic means of detection is very unlikely to alter this situation. With increasingly effective communications, strategic submarines will thus become more secure and more reliable. These same factors, plus a new generation of submarine-launched cruise missiles, will make attack submarines more effective, and will render the protection of surface battle groups and convoys more difficult, expensive and problematic.

Furthermore, both the United States and the Soviet Union will develop and deploy very accurate cruise missiles, using "stealth" technology to attain very low radar cross sections. The Soviet Union will in all likelihood continue to expand and modernize its large air defense system. However, our judgment is that the ability of cruise missiles to penetrate defenses will continue to outstrip the capabilities of defenses against them. The United States will retain confidence in the ability of its air-breathing force of modern, long-range cruise missiles to deliver massively destructive ordnance.

Both countries will extend and vary their passive military use of space for intelligence, communications, navigation, early warning and threat assessment; and they will enhance the effectiveness of their conventional forces with improved surveillance and target identification.

Despite any expanded deployment of strategic defenses, societies will remain vulnerable to nuclear destruction. Technology capable of providing a limited but fairly effective defense of hardened military targets against light attacks will be developed and tested, but it is impossible to say now whether strategic defense will eventually provide an effective or preferred means to enhance the survivability of retaliatory forces. The progress of arms control negotiations in achieving limits on offensive forces, together with further advances in technology, will be central to answering this question.

Assuming these to be the most significant strategic arms trends over the next two decades, the task for the United States is to determine what force design and what arms control measures are best suited to the attainment of a survivable deterrent force and stability in the overall balance of forces. This entails evaluating the contributions to strategic stability of the major weapons systems.

III

One of the principal engines of instability in the nuclear arms race is the preoccupation with strategic counterforce targeting. "Counterforce" refers in general to one’s ability to attack and destroy the military strength of an opponent, thereby limiting the damage one will suffer if attacked. It is frequently argued that such a war-fighting capability strengthens deterrence, and that it would be needed in the event deterrence failed; in some quarters counterforce targeting has also been presented as a "moral alternative" to targeting cities and many millions of innocent civilians. But counterforce weapons pose a dilemma: if deployed in large numbers, they threaten the destruction of a significant part of an opponent’s strategic deterrent forces, namely, his command-and-control system, his fixed land-based ICBMs, his bomber force and his submarines in port. This threat is sufficiently ominous as to have a tendency to undermine the basis of deterrence, especially when the counterforce weapons are high-technology ballistic missiles with short flight time, high reliability and great accuracy. Over the past two decades this threat has generated a preoccupation with securing strategic offensive forces against such massive first strikes.

In evaluating the counterforce threat, one must ask the question: Can a significant fraction of one’s deterrent forces be placed at risk of effective elimination by the attacker at some cost he will find reasonable? One must ask this question about the components of one’s strategic forces and their associated command-and-control facilities. The latter have been the object of much recent concern since, if they can be eliminated swiftly by direct attack, the effectiveness of one’s entire deterrent force can be degraded. But because effective attacks against specific command-and-control targets can be executed by small numbers of strategic weapon systems this problem cannot be solved by setting numerical limits on offensive forces alone.

Both the United States and the Soviet Union take extensive and various precautions to guarantee their ability to control their deterrent forces, even under attack. Coordinated attacks on missile-launching submarines are now, and will probably remain, impossible to execute because of limits to the capacity for antisubmarine warfare. Bombers, on the other hand, can be attacked with missile warheads that are individually very cost-effective (that is, a single ballistic reentry vehicle can eliminate one or more loaded bombers). But operational considerations of alert and warning, as well as of aircraft dispersal, make it difficult for an attacker to rely with great confidence on an ability to destroy preemptively a large fraction of the opponent’s bombers. On the other hand, protection of the bombers against the threat of preemptive attack is expensive; the United States has so far sought to balance economy and security. In essence, the United States can resolve this dilemma unilaterally—for example, by providing more dispersal bases.

In sum, there are unilateral remedies to most of the threats of counterforce attack, although the remedies require extensive planning and are expensive. Broad efforts to secure command and control must continue, and modernization of airborne strategic forces must emphasize their survivability. This still leaves the peculiar fixation on the "window of vulnerability" imperiling land-based ICBMs, a case that epitomizes the logical dilemma of counterforce targeting.

ICBM vulnerability has arisen from two developments: multiple warheads (multiple independently targetable reentry vehicles, or MIRVs) and the high accuracy of counterforce weapons. Of these two, MIRVs are the critical factor. Without them an attacker could not hope to do better than break even; the destruction of a single missile would require the expenditure of at least one attacking missile. In a world with only single-warhead ICBMs, and with a comparable number of launchers on both sides, even a high level of missile accuracy would not be very threatening; one would not then need to consider the difficult job of trying to constrain the evolution of technology.

Thus the objective of arms control agreements seeking to enhance stability should be to provide incentives to both sides to shift toward single-warhead ICBMs, within an overall limit on the total number of warheads (ICBM plus SLBM) that each side could use for prompt first strikes. This should be a major objective of force development for both nations; neither side can do it alone. We believe this goal should have a higher priority than that of merely reducing the number of such vehicles.

To summarize, the desiderata arising from considerations of the problems of counterforce are: first, continued guaranteeing of the security of airborne and seaborne deterrents and of strategic command, control, communications and intelligence; and second, elimination of the risks inherent in counterforce targeting of ICBMs. The first requires judicious force development that secures deterrent forces against threats from new technologies and reduces the threat posed by short-warning attacks. There are three approaches to achieving the second objective: reducing the threatening nature of attacks, protecting the missiles themselves against possible attacks (including making them less attractive targets), or removing the ICBMs entirely.

We address the first approach by investigating force developments that reduce the threat to ICBMs, and we explore the terms of the second approach, which hinges on the problem of ICBM basing, a controversial problem of long standing. The third approach—removing ICBMs—we do not view as a practical objective during the next twenty-year period.

IV

The excellent command-and-control characteristics of ICBMs, their large throw-weights (particularly useful for carrying penetration aids, such as decoys and jammers, to be used against defenses), their high reentry velocities, and their relatively low operating costs (below those of SLBMs on a cost-per-warhead basis) all continue to make ICBMs attractive as offensive weapons, even as their monopoly on high accuracy disappears. The costs of protecting them against counterforce attack will likely remove their operating-cost advantage during the next twenty years. But they will always retain advantages by virtue of their distributed deployment and their command-and-control properties. Militarily, they are the weapons of first choice to provide a credible capability for implementing limited nuclear options; that is, their ability to respond in measure to provocation at any level, which we consider a necessary component of deterrence. (This is both less than and distinct from "nuclear war-fighting.") Such ability, plus the obligation they impose on an offense to be complex enough to coordinate attacks against both ICBMs and alert bombers, makes the maintenance of at least some ICBMs advisable.

The questions are: How large should the ICBM force be, and how should it be based? These questions are not independent, and the question of basing does not yet have a clear answer.

The total number of high-velocity warheads (on both ICBMs and SLBMs) should be fixed by U.S.-Soviet agreement. With such an agreement, and with ICBMs based in a highly secure mode, only a small number of ICBM warheads—several hundred—would be needed. If, as at present, the United States relies on an uncertain survivability of its ICBMs in a massive counterforce attack, a thousand or more reentry vehicles on ICBMs would seem to be necessary to provide sufficient survivable warheads. Deploying ICBMs as single-warhead missiles reduces the probability of success of a counterforce attack by requiring the attacker to target and destroy more missiles.

But questions of numbers and of basing become coupled if the eventual choice for basing is mobile missiles. The possibility of either side’s cheating in deployment of mobile missiles would place a high premium on guaranteeing that such ICBMs do not have multiple warheads, a guarantee that should be a high-priority goal of future arms control efforts.

Confident delivery of a massive and simultaneous strike against a missile force based in hardened underground silos and numbering between many hundreds and more than a thousand would present awesome difficulties. Nevertheless, the possibility of such an attack cannot be dismissed. One must ask: How vulnerable is the U.S. ICBM force to actual execution of a disarming first strike? The most that can be said is that, whatever the chances of success of such a strike, those chances will increase during the next two decades in the absence of new constraints. It is therefore inevitable that resources will be devoted to the search for a more suitable ICBM basing mode, one that meets favorable cost-effectiveness criteria as well as force-structure, political and strategic requirements.

There are five classes of options for secure land basing of ICBMs: deceptive basing, deep underground basing, mobile basing, deployment of an active defense, and hardened silos. We regard only the latter three as still being competitive options.

Mobile missiles would be preferable in the single-warhead mode, so that the numerical uncertainty arising from verification difficulties would not be a major concern. Detailed analyses on various mobile-basing schemes for the single-warhead Midgetman currently estimate system costs to be significantly greater than for fixed basing in silos. However, the United States continues to consider the mobile Midgetman deployment, in part because it is argued to be the most economical when costs are calculated in terms of the desired level of surviving warheads against the currently postulated Soviet threat. This conclusion, however, is sensitive to three considerations: a continued high level of ICBM warhead deployment by the Soviets, the availability of a sufficient land area in the United States for basing mobiles, and the hardness of the missile-launcher-transporter system. The inferred cost advantages may no longer be valid, however, if the reductions in strategic missile warheads discussed by Washington and Moscow are successfully negotiated.

Active defense (e.g., defense by antiballistic missile, or ABM, systems) of land-based missiles is another option. It has three major problems. First, on the basis of technology available in the immediately foreseeable future, active defense of ICBMs will have to use interceptors carrying nuclear weapons, which would require a fundamental change from current U.S. insistence on non-nuclear strategic defense systems. Second, before deploying an active defense, the United States would have to develop and test an entirely new system and show it to be cost-effective and capable against potential countermeasures. (Of course, success in developing such a system would mean that the United States could retain its current ICBMs and basing, with perhaps the addition of some new silos; and the system’s cost would very likely be less than that of a new force of mobile ICBMs.) Third, fielding an active defense for silo-based ICBMs would certainly entail abrogating or, at a minimum, extensively revising, the ABM treaty. Even though radar and interceptor technologies are allowed by the treaty, provisions on numbers and basing would have to be changed.

Justification of active defense of silos requires a complex cost-effectiveness analysis: comparing proliferation of the offense and countermeasures with further improvements in the defense. One would have to develop a detailed engineering design of a system before one could determine if a criterion of cost-effectiveness might be satisfactorily met. Our judgment is that, so far, no option that would meet such a criterion has been clearly shown to exist. The difficulty of producing an active defense option is sensitive to the total number of threatening ballistic missile warheads and to advances in technology, such as the development of warheads that can maneuver independently and maintain accuracy. The problem would be easier if the United States and the Soviet Union were successfully to negotiate reductions in the number of threatening warheads.

The final option is to deploy either MIRVed or small, single-warhead ICBMs in very hard silos. Existing Minuteman silos could be rendered substantially harder if they were refitted with smaller missiles. Deployment of single-warhead missiles in hard silos would be consistent with an arms control regime that restricted the United States and Soviet Union to equal numbers of strategic missile warheads. In a circumstance of symmetrical deployment of single-warhead ICBMs, individual missiles would not be sufficiently valuable to be lucrative targets; an attack would cost more warheads than could be destroyed. If only the attacking side retained MIRVs, after a first strike against single-warhead missiles the total expenditure of warheads in an attack would still be greater, but the financial cost could easily be less, depending on the relative cost of the boosters for MIRVs and single warheads. Thus, silo basing also benefits strongly from well-verified limits on total deployments, to prevent the achievement of an advantage in cost-effectiveness through increased numbers of warheads. This option is the least expensive of the three considered. Its strategic attraction is that a greater vulnerability can be accepted for individual targets of lower value, particularly for ICBMs, which would become, by virtue of smaller relative numbers, a strategically less critical component of the deterrent force.

V

Reductions in the ICBM fraction of the deterrent force would make the sea-based forces, both ballistic missiles and cruise missiles, relatively more important to deterrence. The trends discussed above suggest that this will be an effective strategy.

Both the United States and the Soviet Union should be free to allocate warheads between ICBMs and SLBMs within an agreed total as they choose, according to their own technological, geographic and bureaucratic priorities. Subsequently, this total could be lowered gradually without either side losing confidence in its deterrent. Strategic arms agreements should permit continued modernization of allowed SLBM forces in the interim. Providing these missiles with penetration aids and extending their range to include a larger fraction of the oceans in their operating areas will increase confidence in their survivability.

Modernizing SLBMs would also lead to their improved accuracy, and could cause concern about them as an emerging hard-target counterforce threat. If, however, the number of deployed SLBMs were limited, their modernization would not add significantly to the destabilizing nature of the perceived threat. Such deployments could increase the incentive to move away from a heavy reliance on highly MIRVed, fixed, land-based ICBMs toward a more stabilizing force mix. Once ICBMs were reduced to more stable sizes and types, SLBMs could be traded off for cruise missiles, through gradual lowering of the agreed total number of ballistic missile warheads; the threat of counterforce attacks would thereby be further reduced.

VI

Cruise missiles occupy a unique place in strategic weapons planning. First, quantitative limits on sea-launched cruise missiles cannot be accurately verified. Second, cruise missiles have very little, if any, potential for large-scale, prompt counterforce targeting because of their technical characteristics: their low velocity and their vulnerability as targets for various kinds of interceptors. Their low velocity means long flight times through variable atmospheric conditions that cannot be predicted well at the low altitude at which cruise missiles fly. Massive, highly coordinated strikes by cruise missiles against large, geographically diverse targets, such as ICBM fields, would be impractical because of the long warning times the missiles would afford were any of them detected. The likelihood is high (from the attacker’s conservative point of view) that more than a few of the large number of cruise missiles in such an attack would be detected relatively early. Furthermore, if nuclear weapons were to start exploding in a target vicinity, cruise missiles arriving later might not survive; because they are not hardened against various nuclear weapon effects nearly as well as are ICBM reentry vehicles, attack coordination presents an even more worrisome problem for cruise missiles than it does for ICBMs. Finally, the slowness of cruise missiles precludes their use against targets that can reasonably be expected to move—for example, military units, mobile ICBMs or command posts.

Individual hard targets can probably be protected against limited cruise missile attack, because the flight time of cruise missiles allows significant opportunity for detection by airborne early warning and control systems (AWACS) on station near the targets, or by large arrays of tower-mounted radars. Moreover, once located and identified, cruise missiles are relatively easy to destroy. However, such a defense against cruise missiles could prove very expensive; the large number of airborne or tower-mounted sensors and extensive associated systems required for protection of each target preclude this defense from being practical for very large or soft targets and, in particular, for very numerous targets.

Three classes of appropriate targets for cruise missiles remain: cities, industrial facilities and certain high-value military targets—such as submarine bases, airfields, large fuel depots and proposed ground-based laser facilities; all are too large and soft to protect with high confidence against attack by large numbers of cruise missiles.

In sum, although cruise missiles can inflict massive damage, they are far less threatening against an opponent’s deterrent force than are accurate, reliable and highly MIRVed ICBMs. Since any cruise missile attack might be detected with significant warning time, the attack planner cannot rely on a doctrine that depends on minimal or no warning. The realistic prospect that there will be a long warning time of a large cruise missile attack is an essential element in increasing the stability of deterrence, since it reduces the odds that decisions will be made impulsively on the basis of incomplete information; it also enhances the perceived survivability of most strategic military forces and support elements.

One can argue that cruise missile forces have an important and undesirable defect: the fact that their precise numbers are not accurately verifiable rules out prospects for negotiating tight numerical limits on the levels of deployment, particularly for sea-launched cruise missiles. However, because nuclear-armed cruise missiles are inappropriate for executing large-scale prompt counterforce attacks, there is no strong incentive to enlarge a cruise missile-centered force to anything like the extent of the currently deployed strategic ballistic missile force.

By accepting the evident defect of an inability to count cruise missiles precisely, one could take advantage of these missiles’ stabilizing characteristics, making it possible to accept an arms control regime that would prescribe no limits on certain classes of cruise missiles and shift the emphasis of deterrence to a force structure with far fewer ballistic warheads. Within such an approach, one could continue to implement numerical limits, with satisfactory standards of verification, on air-launched cruise missiles and their carriers. The threats posed by ALCMs are relatively symmetric, assuming that long-range ALCMs will retain their ability to penetrate existing and prospective Soviet air defenses.

Sea-launched cruise missile deployments can be diversified by basing them on surface ships as well as submarines, a process that has already begun. Frequently expressed opposition to extending deployments of nuclear-armed SLCMs to surface ships has generally arisen from three sources: fear of further expanding the size of the nuclear arsenal in unverifiable ways; concern that major surface ships bearing nuclear-tipped SLCMs would be tempting and vulnerable targets; and concern for the physical security and control of the surface-deployed weapons themselves.

The first concern is largely moot, since some SLCMs have already been deployed. Removing them is an unrealistic solution within the near future, since the essentially unverifiable nature of the SLCMs will not be changed by wishing the situation were different. A total ban on SLCMs of all kinds, conventional as well as nuclear, on surface ships might change this reality, but such a ban seems a highly unlikely prospect. Furthermore, the importance of diversification of SLCM carriers will increase as SLCMs become a larger fraction of the deterrent forces.

With regard to the second concern, about the relative risks of SLCMs on ships, there is no reason to believe that, in general, they should be more attractive as targets than other classes of seagoing nuclear forces, particularly aircraft carriers. Concerning the third point, the physical security and control of the weapons can and should be greatly improved with permissive action links (safety devices that prevent the firing of a nuclear weapon without presidentially delegated authorization) like the ones currently employed in the U.S. bomber force.

One aspect of SLCM deployments tends to favor the Soviet Union: a large fraction of the American urban and industrial base, in contrast to that of the Soviets, lies relatively close to the seacoasts, and thus to potential launch areas for SLCMs. The significance of this asymmetry can be reduced, though not altogether removed, by developing longer-range SLCMs.

Once the total number of ballistic missile warheads has been reduced to a mutually acceptable minimum, thus removing concern about a disarming counterforce attack, future reductions in nuclear weapons could proceed by eliminating the right for certain classes of ships to carry nuclear-armed SLCMs. The progress of such restrictions can be adjusted to guarantee a stable regime as verification capabilities evolve and as numbers of weapons decrease. Finally, if adequate SLCM-counting methods are developed, restrictions can accommodate U.S.-Soviet geopolitical asymmetries by providing freedom to allocate between ALCMs and SLCMs under an agreed total.

VII

The critical practical issue surrounding strategic bombers continues to be the perceived necessity for the ability to penetrate all the way to the target. This is a problem for efficient force modernization, but one that bears little direct relation to strategic stability. We fail to see the necessity to carry pilots and large, expensive vehicles all the way to strategic targets.

The continued case for high-performance penetrating bombers seems to hinge on four major arguments: (1) the combination of bombers and ALCMs puts a great stress on air defenses, thus providing maximum penetration for both (and causing continued heavy Soviet investment in air defenses); (2) bombers can find mobile targets or be redirected to secondary targets, whereas ALCMs cannot; (3) bombers continue to be needed for other missions (as, for example, B-52s were used in Vietnam); and (4) because of the insufficient range of ALCMs, bombers must penetrate Soviet air defenses even to launch cruise missiles. In our view, none of these arguments makes a compelling case for continuing the development of new penetrating bombers. Extending the range of ALCMs beyond 2,000 miles, a feasible option, would entirely dispose of the fourth argument.

The third argument—conventional use—is indeed a valid reason to keep some bombers in the force. But the requirements are different from those for a bomber force capable of penetrating the world’s heaviest air defenses during a nuclear conflict. The military requirements of the United States for a new, highly versatile, large-payload bomber for combat support and long-range naval attacks do not appear to have been carefully analyzed apart from the assumption that the bomber must penetrate the airspace of the Soviet Union.

Furthermore, to locate a mobile target, a bomber pilot would have to be quite close indeed, about an order of magnitude closer than the distance at which radar can currently acquire airborne targets. Although a bomber may penetrate toward a target at high speed and low altitude, at a speed of several hundred miles an hour the ground close by is a complete blur for a pilot, who would have to slow down to see anything and gain altitude to increase his field of view. Both of these actions would vastly decrease the bomber’s survivability, even if it were a stealth aircraft.

Arguments for the importance of placing stress on Soviet air defenses are highly sensitive to what one assumes to be the relative potential for successful penetration by bombers as compared to ALCMs, and to the additional costs the Soviets must bear to be able to intercept both. To support the argument quantitatively, one must assume either that bombers penetrate very much better than ALCMs do, or that Soviet expenditures to cope with the dual threat would be significantly larger. Neither has been shown to be true.

As is the case with SLCMs, expansion of the role of ALCMs as the airborne leg of the strategic triad will not come without cost. Airplanes designed or adapted for use as ALCM carriers would have attendant costs, although the costs certainly will not equal those necessary for a new generation of penetrating bombers. The savings from eliminating the penetration requirement for bombers could more appropriately be spent in increasing the survivability of ALCM carriers—for example, with more dispersal bases. The air-breathing leg of the triad is the most expensive per warhead, but its unique capability to be recalled, plus its excellent survivability and reliability, will continue to be valuable.

VIII

The scope and pace of strategic defense activities will depend on the future of the 1972 ABM treaty. If the treaty is modified or abandoned in order to allow the full, unrestrained development of new technologies, competition in defensive programs will increase and create new pressures for expanding offensive missile forces and for improving their ability to penetrate any initial deployments of defenses. Advanced interceptors, such as the Soviet SA-12, might provide a partial defense against SLBMs, depending on their deployment mode (including extensive internetting with other systems, especially an expanded deployment of acquisition radars) and on their performance against offensive countermeasures (including radar suppression and trajectory changes). In this light, actual deployment of these weapons will have to be monitored carefully if the current ABM treaty regime is to be maintained.

The one strategic defense technology with tested military capability—nuclear-armed interceptors—is not capable of a significantly more ambitious role than to defend hard points, preferably of dispersed target sets such as ICBMs. The United States must solve two problems in order to consider any significantly more capable defensive system: it must develop means of discrimination in midcourse between attacking reentry vehicles and their accompanying decoys; and, for a full nationwide defense, it must develop a reliable, survivable means of intercepting missiles in their boost phases. Even though other major issues will remain, if these two problems can be solved in the next decade or so it will be possible to evaluate realistically the full military capability of various classes of ballistic missile defense systems.

Meanwhile the primary question remains the size and direction of research and technology development for strategic defense, including testing of functional prototypes. Maximizing the eventual utility of defenses will require negotiating simultaneously to reduce offensive forces and to extend and strengthen cooperation in arms control with the Soviet Union. Such cooperation would play a critical role in determining any future deployment plans. For the coming decade, a research and development program consistent with the ABM treaty is sufficient to fill this need.

Strategic warning, photoreconnaissance and communications satellites are among the most valuable of U.S. military assets. Guaranteeing their security and strengthening their capabilities by vigorously exploiting advancing technology should therefore be among the highest of U.S. defense priorities. The principal means for providing such protection are moving the satellites (except for photoreconnaissance satellites) to higher orbits, applying various kinds of stealth technology, using hardening measures (which would be particularly effective against directed-energy weapons and other forms of electromagnetic attack), providing redundance of means for performing tasks, and maintaining ready spares (and attendant expendable launch vehicles) to replace lost assets. We remain skeptical about the real value of keep-out zones and shoot-back defensive satellites, but further thought and research in all areas of satellite protection will be valuable.

IX

If nothing is done to change the present course, we foresee a continued evolution of existing strategic nuclear systems toward higher capabilities and larger numbers that, taken as a whole and unconstrained, will pose a greater threat to the security of the superpowers and thus a greater threat to peace.

As for remedies, we are suspicious of proposals that attempt to transform or eliminate the source of insecurity with bans on single types of weapons or on new technology. Adaptations and constraints on the applications of a variety of technologies are likely to be more possible to achieve; their ramifications can be more confidently understood.

Therefore, we propose a conservative and evolutionary response to an evolving threat: specific bilateral agreements and judicious unilateral choices in force modernization. We recommend bilateral agreements to reduce drastically the total number of warheads on ICBMs and SLBMs; to limit mobile ICBMs to single-warhead missiles; to permit modernization of SLBM forces, with a primary emphasis on improved operational security and survivability; and to increase bomber survivability by providing more dispersal bases. We also favor expanding cooperative means of verification, particularly on-site inspection and presence; strengthening survivability and multiplicity of command-and-control systems; and protecting space assets by a variety of means, principally redundancy, ready spares and higher altitudes.

Cruise missiles play a prominent role, in our view. We advocate reducing the role of both ICBMs and SLBMs, with the result that the bulk of the U.S. deterrent force should comprise two categories of cruise missiles, ALCMs and SLCMs. In addition, the air-breathing deterrent should move from a penetrating bomber force toward an advanced ALCM force.

Our approach is not to be interpreted as recommending an unlimited increase in numbers of SLCMs and their carriers. We believe that, in fact, the numbers will remain within reasonable limits and that the operational aspects of deployment can be made and kept strategically stable.

Unilateral actions by the United States to ensure a high survivability of the independent components of the American deterrent force are more important than seeking to negotiate rigorous equality in the numbers of warheads. We anticipate a political evolution toward deeper numerical reductions as both sides develop operational confidence in cooperative measures of verification, including such measures as challenge rights and on-site inspection.

None of our suggestions would stand in the way of the various current proposals for significant reductions in total deployed nuclear forces. Evolution toward force structures that simultaneously are inherently secure and give long warning time in the event of a massive attack will not only be stabilizing, but also will remain a source of stability as total numbers of weapons decrease. We believe that the limited proposals we make here for managing the strategic balance in the near term can provide a practical basis for subsequent steps toward smaller and more stable strategic forces.

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  • Sidney D. Drell is Professor and Deputy Director of the Stanford Linear Accelerator Center and Co-Director of the Center for International Security and Arms Control, Stanford University. Thomas H. Johnson is Professor of Applied Physics and Director of the Science Research Laboratory, U.S. Military Academy, West Point. He is a member of the Center for International Security and Arms Control. This article is adapted from a more detailed study forthcoming from the Center for International Security and Arms Control, Technical Trends and Strategic Policy.
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