Nuclear Policy and the Defensive Transition

On March 23, 1983, President Reagan delivered a televised speech to the nation in which he initiated a potentially radical departure in U.S. strategic policy. The President suggested that the policy of nuclear deterrence through the threat of strategic nuclear retaliation is inadequate, and called upon the vast American technological community to examine the potential for effective defense against ballistic missiles:

Would it not be better to save lives than to avenge them? Are we not capable of demonstrating our peaceful intentions by applying all our abilities and our ingenuity to achieving a truly lasting stability? I think we are-indeed we must.

After careful consultation with my advisers, including the Joint Chiefs of Staff, I believe there is a way. . . . It is that we embark on a program to counter the awesome Soviet missile threat with measures that are defensive. Let us turn to the very strengths in technology that spawned our great industrial base. . . . I know this is a formidable technical task, one that may not be accomplished before the end of the century. Yet, current technology has attained a level of sophistication where it is reasonable for us to begin this effort.1

The central problem of nuclear deterrence is that no offensive deterrent, no matter how fearsome, is likely to work forever, and the consequences of its failure would be intolerable for civilization. The President's call was a direct challenge to the offensive concept of deterrence that has dominated U.S. strategic policy for decades. That concept is based upon the simple and still widely accepted argument that neither the United States nor the Soviet Union will launch a nuclear first strike or engage in other highly provocative actions if both sides are vulnerable to nuclear retaliation. The President's speech suggested that vulnerability to a Soviet nuclear attack is not an acceptable condition in the long term, and that the United States would examine avenues to counter the threat of nuclear missiles.

Following the President's speech, National Security Study Directive 6-83 mandated an examination of the technology that could eliminate the threat posed by nuclear ballistic missiles to the security of the United States and its allies. Accordingly, between June and October 1983, two studies assessed the technical and policy issues of a national commitment to ballistic missile defense (BMD). James C. Fletcher, former administrator of the National Aeronautics and Space Administration, headed a Defensive Technologies Study Team, and Fred S. Hoffman, director of Pan Heuristics (a policy analysis organization based in Los Angeles), led an extragovernmental Future Security Strategy Study. A senior interagency group integrated the two studies, and on behalf of Secretary of Defense Caspar Weinberger and then National Security Advisor William P. Clark, recommended a technology development plan to the President. The interagency group reportedly advised a vigorous research program to support an early decision concerning BMD development and deployment options, and recommended funding estimates for Fiscal Year 1985 through FY 1989 ranging from $18 billion to $27 billion. The interagency group apparently estimated the total cost, through deployment, of a multilayered defensive system to the year 2000 at approximately $95 billion; a recent Department of Defense study, however, has placed the cost of a laser defense for U.S. cities much higher.2

On January 6, 1984, President Reagan reportedly signed National Security Decision Directive 119, which authorized an expansive research program to demonstrate the technical feasibility of intercepting attacking enemy missiles. The President has requested $1.99 billion for the "strategic defense initiative" for FY 1985, a level of support that is $250 million above the budget figure for FY 1984.

Although a small core of strategic defense enthusiasts has always been present within the U.S. defense community, this level of officially expressed interest in strategic defense is an unprecedented development in recent U.S. strategic policy. The goal of actively defending the American homeland in the event of nuclear conflict has not received serious official endorsement since the 1960s. Also unprecedented is the fact that the President has set policy in front of technology. If the United States does, in fact, deploy a multilayered system for defense against ballistic missiles, it will be the result of policy leading technology, not the more familiar "technology creep" generating enthusiasm and a constituency for a weapons system which then "finds" a policy rationale as it is developed.

In essence, what would be involved would be a new direction in U.S. nuclear policy, a transition period of possibly two decades, involving a new and serious commitment to strategic defensive forces. Of course, such a commitment could not limit itself to countering the threat from ballistic missiles, but would also call for greatly improved capabilities to defend against strategic bomber and cruise missile threats.

Strategic defense has not been debated seriously since the anti-ballistic missile (ABM) debate of 1968-1971. Many of the technological, political and strategic factors pertinent to the old debate have changed considerably since then, but the key issues remain unchanged. They are:

-What role is ballistic missile defense expected to play;

-What effect will a commitment to strategic defense have on stability;

-What is the role of strategic offensive forces during and after a defensive transition;

-How are the European allies likely to react;

-What is Soviet policy concerning ballistic missile defense, and how is the Soviet Union likely to respond to an American initiative; and finally,

-What are the arms control implications of a defensive transition?

II

The role that strategic defense might play in U.S. national security policy is now a contentious issue. Should it be expected to provide an "astrodome" covering American military forces and cities comprehensively, or is a more limited objective acceptable, such as only defending U.S. retaliatory weapons? The criteria for defense effectiveness have profound implications for the research programs to be pursued and the types of defensive systems to be deployed.

For example, if a comprehensive defense for the American homeland is the only objective deemed worthy of the cost, then "exotic" defensive technology such as space-based, directed-energy beam systems or hypervelocity guns will be essential-technology that may take many years to mature. If, however, a more limited defensive mission is endorsed, such as the defense of U.S. retaliatory forces against a Soviet first strike, then more conventional ground-based systems incorporating radars, infrared sensors, and rocket interceptors would be appropriate. Proponents of the "astrodome" approach fear that the diversion of attention toward less sophisticated and less effective systems could harm the chances for the deployment of any defensive forces. They feel that the promise of a comprehensive defense of cities by exotic systems and the transcending of offensive-oriented deterrence is a goal that will capture the imagination and support of the American people-support that should not be jeopardized by discussion of limited defenses for U.S. retaliatory forces.

A limited defense for U.S. retaliatory forces, however, need not be inconsistent with a future exotic defense of cities. Indeed, the two roles and systems would be highly compatible, perhaps essential to a stable defensive transition. A comprehensive BMD system would require multiple defensive layers, including conventional earth-based rocket interceptors as well as exotic beam technology. Such a system would use multiple tiers of defensive protection, intended to intercept Soviet missiles during different phases of flight: the boost and post-boost phase, early and late mid-course, and the terminal phase of flight. More or fewer defensive tiers could exist depending upon the number and types of systems deployed. The layering of defensive forces into multiple tiers of interceptors could provide an extremely capable system for defense. For example, five tiers of defensive interceptors achieving 85-percent effectiveness in each layer would reduce the overall attack to less than .01 percent of the original number of attacking weapons. If 10,000 nuclear warheads were launched at the United States with such a multilayered defensive system in place, at most a single weapon would be likely to penetrate to its target.

Current, more conventional earth-based BMD technology is relevant to the interception of warheads at various points in the mid-course and terminal phases of missile flight, but it does not promise effectiveness in the boost phase, wherein an attacking missile would be intercepted prior to releasing its host of individually targetable warheads (MIRVs). Intercept during this stage exerts great defensive leverage over the attacking force because each missile destroyed eliminates all the warheads carried by that missile.

Nevertheless, near-term BMD technology could provide the means for the important lower tiers of conventional defense designed to defend U.S. intercontinental ballistic missiles (ICBMs), strategic bomber bases, and selected critical command, control and communication facilities. These ground-based defensive systems designed to intercept Soviet warheads in their mid-course and terminal phases of flight would likely be non-nuclear, i.e., they would not use nuclear-tipped interceptors, and could be available by late in this decade. The deployment of such near-term defenses for limited coverage would actually help to facilitate a subsequent commitment to a more comprehensive defensive system involving exotic space-based systems.

The period of transition to a comprehensive defense incorporating additional layers of more advanced defensive technology could require two decades or longer for full deployment of the systems. It must be recognized that this transition period could be dangerous if precautions were not taken to ensure political and strategic stability during that period. The Soviet Union, for example, is likely to achieve an initial temporary advantage in defensive capability given its existing extensive radar network and rapidly deployable ground-based BMD. A unilateral Soviet BMD system of even limited effectiveness could be highly destabilizing in the context of existing Soviet offensive first-strike capabilities and extensive air defense and civil defense preparations: the U.S. deterrent threat could be severely degraded by the combination of the Soviet first-strike potential to destroy American strategic nuclear forces and a Soviet defense against surviving American forces.

This combination of Soviet offensive and defensive capabilities could increase first-strike incentives during a crisis if Soviet leaders were persuaded that the U.S.S.R.'s defenses might be capable of largely absorbing the much-diminished U.S. retaliatory capability. Admittedly, Soviet strategic defenses on a modest scale could do little to limit damage against a coordinated and large-scale attack by undamaged U.S. offensive forces; but alerted Soviet defenses could be very effective in defending against a U.S. force sharply reduced in size and impaired by a Soviet first strike.

Thus, early deployment by the United States of a ballistic missile defense for its retaliatory forces would not only help to ensure the survival of U.S. strategic weapons, but would also assist in preserving the credibility of the U.S. offensive deterrent during an otherwise potentially unstable transition period. Even such limited conventional defensive coverage for U.S. retaliatory forces would create enormous uncertainties for Soviet planners considering the effectiveness of a strategic first strike, in addition to those longstanding doubts pertaining to the calculated effectiveness of their offensive forces.3 In the context of Soviet defensive deployments, enhancing the survivability and potential effectiveness of U.S. retaliatory forces by means of both strategic defense and more immediate special "penetration aids" for offensive weapons would help to ensure that a transition to a comprehensive defensive capability could be pursued safely.

The crucial role played by U.S. retaliatory forces to safeguard stability during the initial phase of a defensive transition should also be clear. MX-Peacekeeper intercontinental ballistic missiles, a new small ICBM, B-1B bombers, cruise missiles, and Trident submarines are essential for deterrence stability during the decades of transition. New defensive weapons should not be considered a substitute for, or alternative to, the current modernization of strategic offensive forces; indeed, a strategic defensive initiative necessitates modernization of offensive forces to help sustain stability during the defensive transition. The leaders of the Soviet Union are likely to share this view.

Finally, a transition to a comprehensive defense for the American homeland would require the support of many Administrations and necessitate major technological advances. Completion of such a transition could be waylaid for technological or political reasons over the course of the decades that any such transition will require. As a result, each phase of a defensive transition must be valuable in and of itself, and should complement any subsequent investment in strategic defense. Early deployment of BMD coverage for U.S. retaliatory forces would constitute the first phase of a comprehensive defensive transition; it would safeguard the process of transition, and would be strategically valuable on its own merits, even if subsequent phases were delayed or terminated for political or technical reasons.

An important by-product of a ballistic missile defense system, even of limited effectiveness, is protection of the United States (and Soviet Union) from the accidental launch of a missile. For both sides to be protected against an accident would be far preferable to the current condition which carries a very high risk that disastrous consequences would follow from any such mishap. Further, limited BMD could help protect the United States against lightly armed nuclear powers of the future.

There are dozens of technical possibilities for future strategic defense systems; the debate over the proposed defense transition is not about the prospective effectiveness of one or two systems. Faced with the very rich menu of technical options for defense, it is simply untenable to assert that "they" (ground-based conventional interceptors and beam weapons, and space-based or deployable directed- and kinetic-energy weapons) will not work. Very near-term technology almost certainly could effectively provide limited but important defensive coverage for U.S. strategic forces.4

The more sophisticated exotic technology necessary for a comprehensive defense, although still in its infancy in some regards, shows tremendous potential. Commenting upon the recent classified governmental studies reviewing BMD, the President's Science Advisor, Dr. George Keyworth, noted:

We can now project the technology-even though it hasn't been demonstrated yet-to develop a defense system that could drastically reduce the threat of attack by nuclear weapons, not only today, but those that could reasonably be expected to be developed to counter such a defense system.5

All of recorded history has shown swings in the pendulum of technical advantage between offense and defense. For the strategic defense to achieve a very marked superiority over the offense over the next several decades would be an extraordinary trend in the light of the last 30 years, but not of the last hundred or thousand years. Military history is replete with examples of defensive technology and tactics dominating the offense.

In sum, different levels of defensive technology can make important, and distinct, contributions to strategic stability. The near-term role for limited ballistic missile defense suitable to the technology likely to be available soon would be to provide protection for the U.S. nuclear deterrent and perhaps protection of the nation against small or accidental attacks. As the initial phase in a transition to comprehensive BMD coverage, defense of U.S. retaliatory forces would help provide the stability necessary for the long-term development of the more effective systems needed for a comprehensive defense of U.S. cities. If the technology for effective city defense proves to be attainable, then strategic defense can expand in scope and depth to provide coverage for urban and industrial America. If so, the limited coverage provided by earlier conventional ballistic missile defense will still be valuable, indeed essential, as a backstop against "leakage" through space-based tiers of defense.

III

What is the likely effect of strategic defense on stability? If the Reagan Administration (or its successors) cannot answer critics who charge that strategic defense would be "destabilizing," it will have little hope of generating or sustaining the necessary congressional and public support. During the initial phase of a defensive transition, stability could be safeguarded by defending U.S. offensive forces and by enhancing their potential to penetrate Soviet ballistic missile defenses.

A more difficult question concerns how stability would be maintained during the later phases of a transition wherein, theoretically, neither side could pose a credible threat to inflict very widespread nuclear destruction upon the other's homeland. Deterrence in the nuclear age has come to be understood in terms of mutual threats of nuclear devastation varying only in kinds of targets, i.e., counter-military, counter-industrial, counter-city, or all of these. The nuclear missile age has so far been an age of defenselessness against these threats. The question now is: could stability be maintained if the current condition of mutual homeland vulnerability were to be altered drastically?

Before addressing this question, it should be noted that neither the United States nor the Soviet Union could have complete confidence in their defensive systems. Exotic defensive systems could fail catastrophically under actual operational conditions. Very sophisticated systems, which must integrate numerous and complex component functions in the face of countermeasures, entail a degree of uncertainty. This uncertainty concerning the operational effectiveness of the total system could persuade leaders of both superpowers that an "unacceptable" level of destruction could still result from a clash of arms. The prospect of a catastrophic failure of the defense, or substantial leakage, should serve as a residual offensive deterrent. It certainly should preclude the possibility that any political leader would believe that the world had been rendered completely "safe" for large-scale non-nuclear war.

If, however, one assumes a very high degree of confidence by U.S. and Soviet leaders in their defensive systems, deterrence should still function, but it would no longer be the long-familiar deterrence from mutual vulnerability. The U.S. deterrent would rest on a defensive capability to deny plausibility to any Soviet "theory of victory." That is, U.S. defenses would thwart Soviet strategy and deny the Soviet Union its requirements for military and political success. These include: the destruction of U.S. military potential such that the Soviet Union, though not escaping damage in nuclear war, would survive, recover, and continue to function; the destruction of opposing forces in Europe; and the seizure of critical strategic assets world-wide.6 Soviet military writers caution against any nuclear "adventurism" in the absence of a capability to meet these requirements for success.

This type of defensive deterrent is not totally removed from the current offensive-oriented deterrent. Currently the United States seeks to deny the Soviet Union its theory of victory by promising a devastating nuclear retaliation. In contrast, a defensive deterrent would deny the Soviet Union its theory of victory by ensuring its inability to defeat the United States-promising a long and potentially unwinnable war which could allow the vastly superior U.S., and U.S.-allied, military-industrial potential to come into play. Soviet leaders are acutely sensitive to the probable negative political consequences of such wars and are highly respectful of U.S. military-industrial potential. The prospect of waging a protracted war would be a deterring prospect for Soviet leaders. Perhaps most important, unlike the current condition, a defensive deterrent would combine the prospect for denial of Soviet victory with the avoidance of U.S. defeat and destruction.

It is difficult to compare the relative efficacy of offensive and defensive approaches to deterrence. The current offensive-oriented deterrent threatens dire short-term consequences, but its credibility is subject to grave doubt. Would an American President actually invite national self-destruction by unleashing U.S. nuclear forces in response to a limited Soviet attack (against U.S. allies perhaps), thereby triggering massive Soviet nuclear retaliation? Some reply with a cautious "yes," others with a skeptical "no." The point is that no matter how the United States refines its offensive-oriented nuclear strategy, it is apparent that American society could not withstand Soviet nuclear retaliation. Consequently, a solely offensive-oriented deterrent must lack credibility vis-à-vis most threats; its effectiveness is extremely constrained.

A defensive-oriented deterrent would not impose comparably dire short-term punishment, but there would be no doubt concerning the credibility of a defensive deterrent being used. Just as no one questions whether NATO's conventional forces would fight if attacked, so there should be no question that strategic defenses would be used, particularly if they were of a non-nuclear kind. It is a matter of no small importance to have forces whose credibility of employment is 100 percent. While it is difficult to compare the relative efficacy of these different types of deterrents, there is one critically important distinction. In the event deterrence fails, extremely effective defenses could enable the United States (and perhaps the Soviet Union) to avoid a nuclear holocaust, while a purely offensive approach to deterrence virtually ensures a holocaust.7

In short, a transition to strategic defense would not be inconsistent with deterrence. Rather it would introduce a different approach to deterrence, an approach that could reduce both the probability and the consequences of nuclear war.

IV

A defensive deterrent would thus present powerful disincentives against a Soviet nuclear first strike. It is likely, however, to be less appropriate for the current policy of extending deterrence coverage to allies and global interests. The U.S. strategic nuclear threat, which is integral to NATO's "flexible response" doctrine, would be less deterring in the presence of Soviet strategic defenses. Moreover, the Soviet Union might believe that the potential benefits of conventional conquest in Europe or the Persian Gulf would be worth the risk if there were a strategic defensive stalemate with the United States. Indeed, control and exploitation of the industrial and energy resources of Western Europe and the Gulf may be seen by Soviet leaders as the way of overcoming their otherwise long-term structural economic disadvantages in the global competition with the United States, notably in the production of military high-technology items.

A possible solution to this potential problem is the same as that suggested for the solution to NATO's current over-reliance upon the threat of nuclear retaliation, namely the enhancement of NATO's conventional forces. That solution has been understood and advocated by every U.S. Administration for the past two decades. The European allies, however, have long resisted incurring the social and economic costs associated with providing NATO with conventional forces sufficiently large, well equipped, and intelligently deployed to compel the Soviet Union to think in terms of a high-risk, high-cost nuclear attack. Instead, NATO Europe has preferred for years to rely heavily on a largely U.S.-provided nuclear deterrent. Should, however, the Soviets develop an effective strategic defense, the U.S. "nuclear umbrella" would appear much less fearsome to the U.S.S.R., compelling Western Europeans to seek an alternate means of preserving their security.

Thus, it is doubtful that America's European allies will ever be enthusiastic about a defensive transition in U.S. national security policy. They are likely to see it as a weakening of the U.S. commitment to provide a nuclear umbrella over Western Europe. Moreover, European countries confront a wider spectrum of threat than does the United States. A BMD system that effectively protected the United States and its European allies from strategic nuclear attack would still leave the Europeans vulnerable to conventional and some kinds of tactical nuclear attack. This asymmetry in vulnerability, and hence the perception of an asymmetry in American and European interests, could be exacerbated by a new U.S. defensive deterrence policy.

A defensive transition by both superpowers would also degrade, perhaps nullify, the British and French independent strategic deterrents. It was clear during the SALT I negotiations that the British and French wanted BMD limited to very low levels so that their relatively small independent nuclear forces would retain effectiveness. There is little to indicate that the British or French have a different perspective today.8

During a defensive transition, however, some of the allies might seek to parallel U.S. and Soviet efforts and acquire their own strategic defenses. French President François Mitterrand apparently indicated interest in strategic defense when he recently stated that a "European space community" with the capability "to fire projectiles that would travel at the speed of light" would "be the most appropriate answer to the military realities of the future."9 The British and French may also adopt a more aggressive "penetration aids" program for their offensive nuclear forces to enhance their effectiveness against Soviet defenses. In the near- to mid-term, however, it would seem unlikely that independent European offensive or defensive capabilities could compete successfully with those of Soviet forces.

On an objective analysis, there are some respects in which a defensive transition could enhance security in Europe. First, U.S. BMD technologies could help protect the Western Europeans from Soviet long-range theater nuclear weapons (such as SS-4s, SS-5s, SS-20s, and variable-range ICBMs and submarine-launched ballistic missiles or SLBMs). Given the relative ease of Soviet military access to Western Europe, such a defense would not be comprehensive, but it certainly could reduce NATO Europe's vulnerability significantly and provide a politically effective counter to the much discussed SS-20.

Second, if America is defended, the President is likely to see a lower level of risk involved in responding to a Soviet invasion of Europe than if America were naked to Soviet nuclear attack. This fact alone should significantly reduce any Soviet inclination to attack NATO Europe. Even though the United States could not pose an "assured destruction" level of threat against the Soviet Union in response to an invasion of NATO Europe,10 the prospect of waging a long war for control of Europe with a defended and mobilized America could not help but be a highly deterring prospect. Thus, the U.S. "extended deterrent" over Europe could still be effective to an important degree.

Nonetheless, the reaction of major NATO countries to a U.S. BMD program would be likely to reflect the concerns already noted, as well as a fundamental difference between American and European perspectives on security. NATO allies have long criticized what they identify as the U.S. penchant for a technological rather than a political solution to security concerns. No matter how sound the strategic case for a defensive transition, many Europeans will be more impressed by the effect a defensive transition might have on the political foundations of the familiar East-West security system.

In sum, many Europeans are likely to prefer what they judge to be the political benefits of détente and an intact ABM Treaty to the strategic benefits that would follow a transition to effective strategic defenses. Ultimately the United States may have to decide whether concessions to the concerns of its allies about strategic defense are worth the price of forgoing the potential for a comprehensive defense and leaving the American homeland vulnerable.

V

How would the Soviet Union respond to an American defensive transition? Would the Soviet Union cooperate, tacitly or explicitly, with a defensive transition, by negotiated reductions in offensive weapons to ease the defense burden, or would it choose to compete comprehensively in an offense-defense race?

First, it should be noted that the Soviet Union has exhibited much more enthusiasm for strategic defense over the past two decades than has the United States. Soviet strategic defensive activities were roughly five times U.S. outlays in 1970 and increased to 25 times U.S. outlays in 1979.11 While the United States drastically reduced its number of interceptor aircraft and de-activated its air defense, surface-to-air missile (SAM) batteries during the 1960s (on the argument that if defense against ballistic missiles was infeasible, there was little point in bomber defense), the Soviet Union modernized and increased its air defenses. While the United States reduced its commitment to civil defense to a marginal level, the Soviet Union expanded its civil defense efforts. Additionally, Soviet offensive-force modernization over the last decade has been directed toward achieving the capability to destroy U.S. retaliatory forces before they could be used-"active defense" in Soviet military parlance. It is apparent that the notion of defending the homeland is central to Soviet strategic thinking.

The Soviet Union has approached ballistic missile defense through two avenues. First, the Soviet Union has maintained, and is now modernizing, the world's only operational ballistic missile defense site around Moscow. Moreover, it has continued to upgrade its extensive network of air defense radars and interceptors (such as the SA-5 and SA-12 interceptors), giving them some capability against strategic ballistic missiles and intermediate-range theater nuclear missiles such as the Pershing II. The United States tried to address this possibility by including articles in the 1972 ABM Treaty prohibiting the testing of air defense components "in an ABM mode." This is a key area where the Soviet Union is alleged to have violated the letter and the spirit of the ABM Treaty by testing air defense radars and interceptors against ICBMs. Recently, U.S. photo reconnaissance satellites discovered a new, gigantic radar under construction near Abalakova that is difficult to explain except as an ABM battle management facility. The location (far from the Soviet periphery) and the direction of this radar appear to be in direct violation of the ABM Treaty.

Second, the evolving Soviet ballistic missile defense research and development program accommodates directed-energy beam systems and a more conventional BMD system involving transportable radars and high- and low-altitude interceptors that could be deployed rapidly.12 The combination of an existing infrastructure of large battle management radars, rapidly deployable BMD interceptors, and transportable missile site radars has led some in the intelligence community to conclude either that the Soviet Union is preparing to "break out" of ABM Treaty constraints and initiate a defensive transition, or is engaged in a "creeping" break-out, to be followed by rapid deployment of BMD.

Yet there are several reasons why it is unlikely that the Soviet Union would be the first to withdraw formally from the ABM Treaty and initiate an overt transition to ballistic missile defense. While the Treaty is in effect, the Soviet Union can continue to pursue its gradual upgrading of air defense to achieve greater ballistic missile defense capability, with less likelihood that the United States will react strongly. This sub-rosa avenue to greater strategic defense would permit the Soviet Union to avoid the political fallout and frantic U.S. response that would probably result from outright Soviet renunciation of the ABM Treaty.

Second, the Soviet Union obviously is aware that for the first time in two decades the United States is making a very serious commitment to explore the technical promise of strategic defense. Soviet leaders may suspect that the United States will petition for revision or withdrawal from the ABM Treaty within the decade. A prudent tactic for the Soviet Union would be to wait for such a U.S. initiative, and then to insist on significant U.S. arms control concessions in return for Soviet endorsement of the revisions sought by the United States. In this case the Soviet Union could achieve a major propaganda success with the charge that it was the United States that had sought to weaken or terminate this important symbol of détente, indeed, this perceived monument to the mutual commitment to prevent nuclear war. Given the enduring West European commitment to 1970s-vintage détente, the Soviet Union could further its traditional objective of dividing NATO by presenting itself as the defender of the ABM Treaty.

Finally, if the Soviet Union should "break out" of the ABM Treaty in the near term, it is almost certain that the United States would respond with deployment of a system based upon current defensive technology. U.S. ballistic missile defense research and development has focused upon ICBM defense for almost two decades, and it is clear that the defense of ICBM silos is within our grasp. The Soviet Union, however, has spent billions of rubles deploying its fourth-generation ICBMs (particularly the SS-18s and SS-19s) for the purpose of putting U.S. ICBM silos at risk. It also is quite clear that the Soviet Union signed the ABM Treaty substantially in order to forestall the potential of the U.S. Safeguard missile defense program, then under deployment to protect U.S. ICBMs from attack. In effect, the ABM Treaty provided Soviet SS-18s and SS-19s unimpeded access to U.S. ICBM silos. With MX-Peacekeeper ICBMs scheduled to go into silos in 1986, it seems unlikely that the Soviet Union would choose to surrender its ability to threaten U.S. ICBMs by abrogating the ABM Treaty. Such a course of action would be reasonable only if the Soviet Union were very confident in the ability of its defenses to intercept U.S. ICBM warheads. In that case, the Soviet Union would not have to rely on its offensive forces to destroy U.S. retaliatory forces and would need to be far less concerned about a U.S. capability to defend its ICBMs.

Given all of these considerations, it would appear unwise for the Soviet Union overtly to break out of the ABM Treaty regime. What then would be the likely Soviet responses to a U.S. defensive initiative? Our judgment is that the Soviet Union would be most likely to pursue a dual-track response-combining arms control and diplomatic initiatives with strong military programs. Such behavior would be in keeping with the traditional Soviet proclivity for pursuing arms control negotiations and a dynamic arms buildup simultaneously.

Specifically (assuming that the United States had gone ahead), the Soviet Union is likely to attempt both to deploy its own BMD systems and to provide effective countermeasures for its offensive forces in order to thwart U.S. defensive systems. If the Soviet Union seeks to maintain its nuclear threat against the United States and to provide strategic missile defense for its homeland, then an effort to provide offensive countermeasures to U.S. defenses is inevitable. If the Soviet Union were able to achieve the capability to nullify the U.S. retaliatory deterrent while maintaining its own offensive threat against the United States, it would have achieved a strategic condition of major military advantage. The United States obviously must guard against such a condition.

Some of the potential Soviet countermeasures include: an attempt to prevent the United States from deploying defensive weapons in space through direct military interdiction; an increase in the number of offensive weapons sufficient to saturate the U.S. defense; and passive protection of Soviet offensive forces to ensure penetration of U.S. defenses.

The first of these options is the least likely, given the risks involved in initiating a war of attrition in space, particularly if the Soviet Union hopes to deploy its own space-based defenses. The Soviet Union historically has not taken direct action in response to U.S. deployment of a new type of military system. A basic precept of Soviet policy is that war is a political phenomenon; it is not a proper response to an American peacetime weapons deployment.

Among offensive and defensive military countermeasures, the Soviet Union might attempt to increase its number of ICBM and SLBM warheads, intending thereby to saturate the U.S. defensive systems. A second tactic would be to attempt to sidestep U.S. defenses against ballistic missiles by increasing the bomber and cruise missile threat. The Soviet Union could also attempt to avoid all U.S. strategic defenses by emphasizing "unconventional" operations (e.g., crisis and wartime sabotage) involving nuclear, chemical or biological weapons.

Finally, the Soviet Union could attempt to provide "passive" protection for its offensive forces against U.S. defensive beam weapons. This could be done, for example, by hardening the missiles, increasing their speed of ascent and thereby reducing their time at maximum risk, adding ablative material to missiles so as to absorb the heat transferred by a high-energy laser beam, or even by spinning the missile during its ascent in order to reduce the dwell time of the laser beam.

If the Soviet Union lacked confidence that it could succeed in this high-technology competition, however, it would have greater incentives to pursue constraints on the United States through arms control. The ABM Treaty is an informative precedent. During the early 1970s the Soviet Union chose to limit U.S. superiority in ABM technology through arms control rather than by relying upon offensive countermeasures alone.

VI

This brings us to the question of the impact on arms control of a determined U.S. BMD program and of the likely Soviet response to such a program. Here the first question is the impact on existing arms control agreements, notably the ARM Treaty.

The United States and Soviet Union would have to revise the ABM Treaty to permit deployment of BMD systems of even limited effectiveness. A comprehensive defense would likely necessitate withdrawal from the Treaty, which Article XV permits on six months' notice.

The United States certainly has sound strategic and arms control reasons to reconsider its continued endorsement of the ABM Treaty. At the time the Treaty was signed, the United States established a clear linkage between offensive and defensive arms control limitations. Such a linkage made good sense; the United States could accept severe constraints on BMD, which might defend U.S. ICBMs and strategic bomber bases, if the Soviet offensive threat to U.S. retaliatory forces could be constrained and reduced on a long-term basis through arms control.

Thus, U.S. Unilateral Statement A, accompanying the ABM Treaty, stated specifically that a failure to achieve agreement within five years, providing for more comprehensive limitations on offensive forces than those contained in SALT I, could be grounds for withdrawal from the ABM Treaty. Unilateral Statement A also said: "The U.S. Delegation believes that an objective of the follow-on negotiations should be to constrain and reduce on a long-term basis threats to the survivability of our respective strategic retaliatory forces."13

Unfortunately the standard thus set by the United States for continued support of the ABM Treaty has not been met. Indeed, the Soviet offensive threat to U.S. retaliatory forces has increased dramatically since the signing of SALT I, and the signed but unratified SALT II agreement would not have eased the problem of strategic force vulnerability given the types and numbers of weapons permitted.

Yet the strict prohibitions on BMD systems that could defend retaliatory forces remain intact in the form of the ABM Treaty. Since the signing of SALT I, the United States has, to a large degree, dismissed the sensible linkage between offensive and defensive limitations established at those negotiations.

Thus, the United States and the Soviet Union do have the legal right to withdraw from the ABM Treaty, given proper notice, and the United States does have a strategic and an arms control rationale for reconsidering the ABM Treaty. The Treaty should not be considered sacrosanct.

If the United States does decide to seek revisions to, or withdraw from, the ABM Treaty to permit extensive deployment of BMD, when would a change in the status of the Treaty be necessary? It is unlikely that revision or withdrawal would be required until relatively late in the 1980s. This is because the ABM Treaty constrains deployment much more severely than it does research and development.

The potential near-term BMD system that could provide limited but important defensive coverage during the initial phase of transition could run into trouble with the Treaty prohibition against testing, development or deployment of mobile BMD components (Article V); certainly actual deployment of any effective system would run afoul of the limitations of Article III, which restrict the number of permitted sites to two (amended to one site in the 1974 ABM Treaty Protocol) and the number of permitted interceptors and launchers to 100.

Although mobility would probably be sought in a near-term BMD system, to ensure survivability, the initial development and testing of subsystems need not be in a mobile mode, and the actual mating of these subsystems to constitute a mobile component or system need not occur until relatively late in the development and testing process. Thus there is no great urgency to revise the Treaty in the very near future. If the United States decides to proceed with the defensive transition, however, it should begin to examine the types of treaty revisions that are necessary, and the appropriate timing for those revisions.

The Treaty does allow great freedom for development and testing (but not deployment) of exotic beam defenses, particularly as long as these are tested from fixed, ground-based installations. Nevertheless, in the long run, if the United States decides to pursue comprehensive BMD coverage using multiple layers of defensive interceptors, the ABM Treaty will be unlikely to survive in anything resembling its current form.

On the other hand, neither the prospective near-term defensive systems considered here, nor later more sophisticated defenses, would require atmospheric testing of nuclear weapons.14 Most of the technologies under consideration are non-nuclear and would not involve space-based "weapons of mass destruction" (i.e., nuclear, chemical or biological). Hence a defensive transition need not run afoul of either the Limited Test Ban Treaty of 1963 or the Outer Space Treaty of 1967, banning such weapons.

In sum, a defensive transition would compel initial revision and in all probability later withdrawal from the ABM Treaty. This could be done legally, and would not be inconsistent with the U.S. arms control position established at SALT I. But the most basic question is its broader impact on arms control efforts, particularly to limit offensive weapons on both sides.

In this broader context, there are several reasons why defense and arms control could be mutually beneficial. A defensive transition could establish a necessary basis for deep offensive force level reductions. First, even limited near-term defense systems designed to protect retaliatory forces could alleviate the verification difficulties associated with deep force level reductions. At current relatively high force levels a degree of ambiguity in the ability to verify an agreement is considered acceptable because only large-scale violations would have a "significant" impact upon the strategic balance, and such violations are likely to be noticed. Reducing U.S. and Soviet strategic arsenals to the level initially proposed by the United States at START (e.g., reportedly, a ceiling of 850 for deployed ballistic missiles) or lower, however, would place a higher premium on each delivery system. At much lower force levels even a relatively small level of noncompliance could have a significant impact upon the strategic balance, and thus be of great concern.

In the context of small numbers of U.S. retaliatory forces, the covert retention or deployment of even a few MIRVed ICBMs could be a threat to the survivability of an important fraction of U.S. deterrent forces, and thus provide the Soviet Union with an increased incentive to strike first. And the importance of very strict verification for deep reductions is incongruous with the increasing difficulty of totally monitoring the deployment of new types of nuclear weapons such as cruise missiles and mobile ballistic missiles. Consequently, in the absence of a defensive transition the U.S. insistence upon the ability to verify an agreement with very high confidence could reduce the chance for any deep arms reductions. A transition to strategic defense, however, would reestablish the condition wherein deception on a very large scale would be necessary before the strategic balance could be jeopardized by cheating. U.S. retaliatory forces that were defended would be less vulnerable to deceptively deployed Soviet forces-hence the need for very rigorous verification standards could be somewhat relaxed.

Second, it is clear that one reason for the Soviet commitment to large numbers of strategic weapons is to achieve a damage-limiting effect through offensive "counterforce" capabilities, i.e., the ability to disrupt U.S. command channels and to destroy U.S. retaliatory forces before they could be launched against the Soviet Union. It is likely that the Soviet Union has been so reluctant to agree to U.S. proposals for deep reductions in heavy MIRVed ICBMs because these weapons are the primary counterforce instruments in the Soviet arsenal. As noted above, damage limitation for national survival is a key objective of Soviet strategic doctrine, and that objective currently is pursued primarily through offensive counterforce preparations.

A defensive transition could provide the damage-limiting capability mandated by Soviet doctrine, with strategic defense replacing offensive forces as the principal means for limiting damage. Strategic defense could, in effect, take over the damage-limitation mission now given to offensive counterforce weapons. Such a development should reduce the long-noted reluctance of the Soviet Union to accept negotiated cuts in its large ICBM force.

Finally, if defensive technology proves to be extremely effective, it could reduce the incentives for the offensive arms competition by rendering it futile. The Soviet ballistic missile defense program of the 1960s probably was truncated because it became apparent that U.S. advances in MIRV technology would easily counter the Soviet defensive system. Thus, U.S. technological advances in offensive systems probably discouraged the Soviets from continuing to deploy what had become obsolete defensive technology. The development of highly effective defensive technology could, and logically should, have a similar impact upon offensive weapons programs.

Of course, a transition to defense could lead to a competition in the development and deployment of increasingly advanced defensive technologies. Nevertheless, restructuring the arms competition toward a "defense race" would have a benign impact upon the catastrophic potential of nuclear war, and would be far preferable to an indefinite continuation of the competition in offensive nuclear arms.

VII

In one other respect, related to arms control, a defensive transition could serve the interest of all mankind in a critically important fashion. A recent study on the "Global Consequences of Nuclear War" indicates that a relatively "small" nuclear war, involving between 500 and 2,000 detonations, could result in climatic changes that would trigger a global catastrophe.15 That number of detonations would reflect the use of only a small fraction of the nuclear weapons in U.S. and Soviet arsenals. Strategic defense is the only candidate answer to this potential threat to humanity. Suggested alternatives simply are ineffective.

The most obvious and effective solution to this danger would be for nuclear weapons never to be used. However, it simply is not within the power of a U.S. President to determine whether a nuclear war will occur. Despite the best efforts of the United States to avoid nuclear war, the Soviet Union or another nuclear-armed country could employ nuclear weapons against the United States or a local foe. The first step in understanding this issue is to recognize that whatever the United States does, or does not do, cannot ensure the prevention of nuclear war. It is beyond reason to believe that all nuclear-armed powers would agree to ban the use of nuclear weapons and abide by that agreement under all conditions.

Equally incredible is the prospect for arms control to reduce the global arsenal of over 50,000 nuclear weapons to numbers below the threshold reportedly necessary to cause a climatic catastrophe. This does not mean that the arms control process has no value for the U.S. pursuit of strategic stability. Rather, what is suggested is that this avenue can hardly be relied on to prevent a climatic catastrophe that might stem from even a "small" nuclear exchange.

In sum, a defensive emphasis and nuclear disarmament are essential allies. Advocates of a radical scale of nuclear disarmament need to appreciate that truly deep reductions in offensive nuclear arsenals would be feasible only in the event of heavy deployment of strategic defensive systems. The United States could never verify strict Soviet compliance with a possible START regime that mandated reductions in offensive forces down to the low hundreds of weapons. But, with strategic defenses deployed, the superpowers could be confident that cheating would have to be conducted on a massive scale before it could provide a capability sufficient to yield important military or political advantage. If we assume that the United States and the Soviet Union will be political rivals for many years into the future, strategic defenses offer the only path to a nuclear disarmament agreement with which both parties could live.

A defensive transition-particularly one including the global coverage that space-based systems or components could provide-would reduce the risk of a global climatic catastrophe by intercepting nuclear weapons after they are launched. Given the fact that nuclear deterrence can never provide the certainty of Stability, and given the reported possibility of climatic disaster resulting even from the limited use of nuclear weapons, transition to a defense-dominant strategic policy should be seen as a moral imperative. At the very least, given the perils of the arms competition in offensive systems, the United States is obligated to seek to alleviate those perils through defense. Success in this venture is not guaranteed, but there would seem to be no excuse for the United States not making the attempt.

VIII

Whether defensive technology will be sufficiently robust to defeat potential active and passive countermeasures is an important issue, one which must be examined before critical decisions concerning development and deployment of potential defensive systems can be made. The preliminary conclusions in this regard, drawn from the recent official reviews of BMD, are quite optimistic about the potential for a robust defense against ballistic missiles. Ultimately, only time and further advanced investigation into the potential for defensive technology and offensive countermeasures will enable us to conclude whether the defense will become again the stronger form of warfare.

Unfortunately, though not unexpectedly, the debate that is shaping up promises to be yet another stale and unimaginative confrontation between those who judge homeland defense to be destabilizing and those who do not. Neither the government nor private commentators are well equipped at present with an understanding of how offense and defense can proceed together in complementary, synergistic fashion for the benefit of more stable deterrence. It is very desirable that those who are strongly committed to President Reagan's vision of an America defended against ballistic missile threats think constructively about the positive roles that U.S. offensive and near-term defensive forces can play both to safeguard the defensive transition and, perhaps, to help stabilize deterrence beyond the transition.

Neither superpower, at least in the early stages of an essentially competitive defense transition, is going to cooperate tacitly in assisting the defenses of the other side to achieve high effectiveness. The United States and Soviet Union have, after all, been involved in an arms competition expressing deep-rooted political rivalry. No matter how great the technical success of U.S. and Soviet defense transitions, the competition between offense and defense will not stop. Neither superpower is likely to abandon permanently all hope of gaining a major advantage by developing both effective offensive and defensive weapons.

One must assume that both the Soviet Union and the United States prefer a condition wherein both their offensive and their defensive capabilities are effective, to a condition wherein only their defensive weapons can perform as intended. Neither side, however, is likely to anticipate an enduring advantage in strategic offensive and defensive systems; both will be constrained to accept much more limited offensive targeting capabilities than now exist. Future missions for U.S. strategic offensive forces may include the following: guarding the defense transition; holding at risk so many high-value assets of the Soviet state that the Soviet leaders perceive a substantial net advantage in negotiating a major bilateral drawdown in offensive forces (thereby assisting the U.S. defense transition); providing an enduring hedge against sudden revelation of weaknesses in defensive systems; and providing some deterrent effect in order to help discourage gross misbehavior by third parties.

The public debate over the orientation of future U.S. strategic policy that was triggered by President Reagan's defense initiative proposal of March 23, 1983, has revealed all too plainly that there are more and less sensible ways to think about defense.

Strategic defense should not be viewed in terms of an all-or-nothing "astrodome." "Star wars" defenses, no matter how great their promise, will not constitute the last move in high-technology arms competition, and strategic defensive technology will not solve the fundamental problems of political rivalry. But strategic defense, embracing a wide range of near-term and far-term weaponry, promises to strengthen the stability of deterrence by imposing major new uncertainties upon any potential attack. In the long run, it holds out the possibility of transforming, though not transcending, the Soviet-American deterrence relationship.

1 The full text of President Reagan's speech is in The New York Times, March 24, 1983, p. 20.

2 Reported in Defense Daily, November 29, 1983, p. 137.

4 For an excellent technical discussion that supports this claim, see Dr. Patrick Friel, "Status of U.S. BMD Technology," a paper presented to the annual conference of the American Association for the Advancement of Science, Washington, D.C., January 6, 1982. See also William Davis, "Ballistic Missile Defense Will Work," National Defense, Vol. 66, No. 373, December 1981, p. 16.

5 Quoted in "Keyworth: Space-Based Defense Possible," Air Force Times, October 31, 1983, p. 29.

6 For an examination of Soviet victory requirements, see John Dziak, Soviet Perceptions of Military Doctrine and Military Power: The Interaction of Theory and Practice, New York: National Strategy Information Center, 1981, p. 28.

7 The qualifier, "virtually," acknowledges the presence of the existing theory of damage control and limitation. To be specific, damage to the American homeland in war might be limited if the Soviet government chose to exercise restraint in its nuclear targeting.

9 Remarks by President François Mitterrand at a luncheon offered by the Council of Ministers of the Kingdom of The Netherlands, The Hague, February 7, 1984. Embassy of France, Press and Information Service, Memo 84/6, p. 8.

10 This assertion rests on the assumption that Soviet technical prowess in BMD is roughly equivalent to postulated U.S. prowess. Given the respective strengths of the superpowers as competitors in the area of military high technology, it is very possible that U.S. BMD will be significantly better than will Soviet BMD. Our argument does not require for its validity that the U.S. achieve and sustain a lead in defensive systems. But such a lead would have beneficial consequences for strategic stability.

11 Central Intelligence Agency, National Foreign Assessment Center, Soviet and U.S. Defense Activities, 1970-1979: A Dollar Cost Comparison, SR-80-10005, January 1980, p. 9.

13 See U.S. Arms Control and Disarmament Agency, Arms Control and Disarmament Agreements: Texts and Histories of Negotiations, Washington: GPO, 1980, p. 146.

14 Presidential Science Advisor George Keyworth recently observed that there does not appear to be an important role for nuclear weapons involved in the transition to strategic defense. This comment was made during Dr. Keyworth's presentation at the Forum on The Future of Ballistic Missile Defense, Brookings Institution, February 29, 1984. His statement appears to be an authoritative refutation of the notion that a nuclear-pumped X-ray laser system would be a critical component.

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