The Strategic Defense Initiative (SDI) is President Reagan’s program to develop a system which could defend the United States and its allies against a nuclear attack. The two books under consideration are the best-known public writings of those who believe that such a system is strategically desirable and technolog­ically feasible. With these books, dissimilar as they are, we find the strongest advocacy for the replace­ment of current nuclear strategy, oriented toward offensive forces, by a radical alternative which would rely heavily on defenses. The information they provide about the technologies that might be used for strategic defense, and the strategies which these technologies might make possible, is welcome and badly needed, for the idea of shifting our security to a greater reliance on defenses, as Reagan’s March 1983 speech sug­gested, would mark a major break with past and present strategic policy. It would probably necessitate a major movement of military assets, and potentially military action, into space. And although there are major differ­ences of opinion on the point, the new reliance on defense would probably be contingent on new, still unproven technologies which are little known and understood outside the community of defense technologists.

What would be the benefits and risks of emphasizing defense in our defense strategy? The President’s speech that called for the creation of the SDI program did not discuss these questions in detail; indeed, very little strategic analysis was done before the speech. The President merely pre­sented his vision of a better policy and called for a program to explore the technical feasibility of that policy. Since the speech, many of the key issues relating to SDI strategy and technology have been identified and explored. Some argue that SDI is a technologically impossible dream that would be extremely dangerous if it were possible. Others believe that limited deployments of defenses could help support a strategy which would still rely strongly on offensive forces, and that such limited defenses are technologically feasible. Still others (Fossedal, Graham, and Jastrow among them) agree that highly effective defenses are techno­logically feasible, and if deployed would create a safer, more secure world for the United States. But even these supporters of SDI differ from each other on many important points.

Fossedal and Graham contend that the United States faces a choice between two diverging paths which are not just strategic policies but different orientations toward the future. One path is a continuation of present strategy, based on offen­sive nuclear weapons and imprecisely character­ized as Mutual Assured Destruction (MAD). According to this strategy, the U.S. attempts to deter Soviet attack by threatening a devastating nuclear response to any attack. This is unaccept­able, Fossedal and Graham argue, because it makes no attempt to protect U.S. citizens if deterrence fails. We must live in constant fear that some conflict will get out of hand, or some accident will occur, setting off a chain of events that leads to a massive nuclear war. This fear paralyzes us, preventing us from taking many actions called for by our political and moral princi­ples. Fearful acquiescence in evil leads to the moral degeneration of the American body politic and to infirmity of purpose in U.S. foreign policy. As Fossedal and Graham put it: “MAD suggests that no one dare even think about power. He who uses it may do some good, but he may also err; he who declines to act need not accept responsibility” (p. 25). According to the authors, Mutual Assured Destruction is part and parcel of a set of policies which has led to U.S. decay and decline, and which must be rejected. The other path, they contend, is strategic defense. This offers not only a superior strategy for the security of the United States and its allies but also means to restore superior power to America-a power which could regenerate U.S. moral purpose and lead to a positive new foreign policy.

To take the path of strategic defense, Fossedal and Graham argue, the U.S. needs to move swiftly to build and deploy a “layered” defense system. This would combine several types of space-based weapons, which could engage and destroy attacking Soviet missiles and warheads during their flight toward the United States, with ground-based defense against any warheads that leaked through. These defenses would be supplemented by U.S. civil defense programs. With the U.S. better protected against nuclear attack by strategic defenses, it would be freer to pursue its foreign policy goals and to act in support of those causes in which it believes. The space layers of the strategic defenses would do more than contribute to the security of the U.S. against nuclear attack, however. They would also be able to protect vital U.S. military capabilities in space (e.g., intelligence, early warning, and communications satellites) and would correct what the authors believe is a dangerous and growing Soviet edge in space.

America should not only move military assets into space as a defensive measure, Fossedal and Graham argue, but should gain control of space militarily and use this advantage to restore Western military superiority. Such a “high frontier” would make it possible for the United States to make a “new effort to take the initiative in promoting security, democracy, and develop­ment in communist and underdeveloped nations.” Space-based strategic defenses would also provide the military power and a secure position from which to roll back Soviet influence: A “properly defended Western alliance would be in a position to promote freedom in the East as it has never done before.” Further, having regained the dip­lomatic and moral (to say nothing of military) initiative, the U.S. “would be the champion of peace and security. We would offer our protective blanket to all nations that hope to escape the horrible consequences of assured destruction” (pp. 110, 111).

Although this review is primarily concerned with their defense strategy, we must note that Fossedal and Graham are not simply interested in creating a better and more secure defense (and offense) for the United States. In addition to protecting our military space assets and projecting American military power globally, U.S. command of space would allow that locale to be used for U.S. economic exploitation-manufacturing, research and development, and energy collection or gener­ation. And this would be only the first step in a great new American adventure which, Fossedal and Graham contend, would revitalize American society and restore the conditions for the spread of freedom in the world. That adventure is presented as being analogous to the conquering and settling of the American West.

America need only repeat what it did on its last frontier, the West. We would have to provide for reasonable means of transporta­tion-a railroad into space. We would have to create human outposts to coordinate and oversee our increasing activity—a town store or post office above the atmosphere. We would have to proclaim, and then demonstrate, our determination to defend the frontier settler and his possessions—a sheriff’s office in the sky. We should be doing this and more anyway, in order to protect the United States and its allies on earth. (p. 83)

Fossedal and Graham argue that the new adventure, like the Westward expansion, would restore sturdy virtues to the American people. Societies not interested in exporting themselves, in ensuring the spread of their virtues and way of life, the authors claim, lose confidence in themselves and their own ways of life. With strategic defenses and the settling of the space frontier, Fossedal and Graham contend, America can renew its political virtue and prepare for victory over the Soviet Union.

Robert Jastrow, a prominent scientist in the NASA space program for many years, has been one of the most vocal and effective supporters of the SDI program. Dr. Jastrow has, in comparison with Fossedal and Graham, more modest goals for strategic defenses, although Jastrow has audacious ends of his own. He supports development of strategic defenses which can render nuclear-armed ballistic missiles essentially useless.

The main purpose of his book is to describe for the general public the most promising strategic defense technologies. The technical discussion is prefaced and concluded by a discussion of strategic policy issues related to SDI. The technical section emphasizes potential space-based weapon systems, discussing the physics of a number of directed-energy weapons (e.g., chemical lasers, neutral particle beam, and x-ray laser) and kinetic-energy kill weapons (e.g., hit-to-kill rockets and rail-guns). Jastrow also sketches some of the ways in which the tactical and technical requirements for the “system architecture” might be met. These elements (including surveillance, target acquisi­tion, kill assessment, self-defense, battle manage­ment, and command and control) are needed to allow a complex, many-layered defense system to be controlled and operated effectively even in the face of a determined attack.

Jastrow is only partially successful in translat­ing his understanding of the science of strategic defense for the public. Many of the new defensive weapon concepts are based on complex physics beyond the ken of the general public. In trying to develop explanations and analogies to make these concepts accessible, he has cut a lot of corners, allowing him to be criticized by anti-SDI scientists. Yet the descriptions are too brief and general to educate the inquisitive reader.

Jastrow begins his strategic arguments from the same premise as do Fossedal and Graham-that Mutual Assured Destruction characterizes the current strategic condition. Unlike them, however, Jastrow is not troubled by the domestic and foreign policy consequences of MAD, for MAD implies a strategic balance between the U.S. and the U.S.S.R. and hence deterrence and stability in international relations.

Strategic stability is usually defined as a situation where neither nuclear superpower can, in a first strike, hope to eliminate the other side’s ability or will to retaliate in a manner the first striker would find unacceptable. If this condition is met, both sides are deterred from attacking. Crisis stability is assured if neither side, in a crisis, believes that the outcome of a war would be significantly better for it if it struck first than if it awaited the other side’s attack, or avoided war altogether. To adherents of Mutual Assured Destruction doctrine, these conditions are met when both sides retain sufficient numbers of nuclear weapons which can survive a preemptive attack, be launched, and penetrate to cause a level of damage the other side regards as “unacceptable.” The maintenance by the U.S. and the U.S.S.R. of survivable forces capable of inflicting such punish­ment on each other is supposed to provide both strategic stability and crisis stability. If these criteria were accepted by both the U.S. and the U.S.S.R., they would allow for very large reduc­tions of the superpowers’ strategic nuclear arsenals.

Jastrow’s fear, and the basis for his advocacy of strategic defenses, seems to be that the U.S. cannot assure stability in the future on the basis of offensive nuclear forces alone. In his view, the Soviet Union has never accepted the desir­ability of strategic stability or its basis in mutual vulnerability. Instead of following the American policy of limiting the growth of strategic forces and avoiding the construction of a force capable of threatening the other side’s retaliatory forces, the Soviets develop forces and retain doctrines which would allow them to threaten, or execute, a successful nuclear attack on the U.S. It is the Soviet Union’s erosion of the strategic balance, not the principle of a nuclear balance associated with MAD, that Jastrow finds unacceptable. He notes without argument that “[m]any people, including prominent government leaders, see a positive value in keeping nuclear weapons because they have kept World War II from breaking out. At any rate, they see no hope of getting rid of them” (p. 136). Moreover, the presence of nuclear weapons has suppressed the outbreak or escala­tion of nonnuclear wars between the U.S. and the U.S.S.R. because of the risk that any war would lead to a ruinous nuclear exchange. The NATO strategy of flexible response, including the threat of nuclear first-use, relies directly on this threat of escalation to nuclear weapons to help deter nonnuclear aggression.

Not surprisingly, Jastrow goes on to argue that what really counts is not the number of nuclear weapons on either side, but the main­tenance of a nuclear balance between the U.S. and the U.S.S.R. Of this he says:

Today there is a nuclear balance between the two superpowers, with 10,000 intercontinental nuclear weapons in round numbers, in each arsenal. But an equally effective balance would exist if each country had 5,000 such weap­ons. . . . Such is the fearsome power of these weapons, that if each country had only 10 nuclear weapons, a nuclear balance would still exist. And if 10 weapons would deter an attack and keep the nuclear balance, then why not five or one-or zero? The deterring effect of nuclear weapons on aggression is effective all the way down to zero weapons, provided both sides have equal numbers of these weapons at every stage. (pp. 137-38)

But given the preference of the U.S.S.R for a policy based on superior offensive nuclear forces, Jastrow seems to argue that only the commitment of the U.S. to strategic defenses will demonstrate the futility of this policy and provide the leverage necessary to get the U.S.S.R. to accept a policy based on balance and stability. The development and deployment of strategic defenses by both the U.S. and the U.S.S.R. would then allow for a safe, confident, mutual reduction in offensive nuclear weapons. Even moderately effective defenses would provide nearly perfect protection against attacks using the small numbers of weapons that might be secreted, and thereby negate the effect of any modest cheating on disarmament agreements. Consequently, defenses would provide the confidence required for both sides to engage in real, substantial reductions in offensive arms. A coordinated build-up of defense and build-down of offenses would put us on the path toward nuclear obsolescence.

And what of the role of offensive nuclear weapons in keeping the peace and extending deterrence to U.S. allies? According to Jastrow, that role would not be endangered for a long time. If both the U.S. and the U.S.S.R. deployed 80 percent effective defenses, meaning we could destroy 80 percent of the missiles the Soviets launched at the U.S. in any attack, most of the U.S. retaliatory force would survive and could be launched in retaliation. Even if Soviet defenses intercepted 80 percent of our retaliatory strike, the remaining missiles would be enough to devas­tate the U.S.S.R. As Jastrow says, “They will know that if they attack us, we will be able to strike back with our nuclear weapons and reduce all the major Soviet cities to rubble in thirty minutes” (p. 15). In other words, the practical result of strategic defenses, for a considerable period of time, would be the restoration of a confident mutual assured destruction posture. But this raises two disturbing questions. First, is a nuclear balance really sufficient to allow the U.S. to meet its strategic requirements? As Jastrow noted, U.S. strategic policy provides for first use of nuclear weapons if necessary in response to aggression, and to escalate and control a nuclear war. How we might achieve these tasks in the face of a nuclear balance or Soviet superiority, even with a very large and diverse nuclear arsenal, has been one of the central ques­tions in U.S. strategic policy for many years. With very small, balanced nuclear forces or no nuclear weapons, we certainly could not do these things at all. Second, at some point in the reduc­tion of offenses and deployment of defenses that Jastrow proposes, both the U.S. and the U.S.S.R. would lose all fear of nuclear war—that is, the threat even to incinerate each others’ civilian population would be negated. Jastrow notes without demur that many people believe the fear of nuclear war contributes importantly to the prevention of both nuclear and nonnuclear war between nuclear weapon states. What would be required to maintain American security in the complete absence of offensive nuclear arms? We never get a clear answer to these questions, and for this, How to Make Nuclear Weapons Obsolete has sometimes been criticized.

These two volumes present sharply differing defense strategies which might be made possible by the successful development and deployment of strategic defense technologies. While both are valuable attempts to work through this difficult new subject, neither strategy is completely con­vincing as it now stands. The Fossedal-Graham strategy, the objectives of which are much larger than just supplying an adequate defense, would require the U.S. to gain control of space and use that control as the high ground from which to exercise a decisive military advantage over the Soviet Union.

Achieving such a strategy would require overcoming some major hurdles. The first is that, as Fossedal and Graham note, the U.S. has fallen behind the U.S.S.R. in some important areas of military power. The authors advocate rapid development and deployment of defenses, but there is considerable doubt within the defense community whether the sorts of weapons which they advocate building in the next several years will be effective enough to implement their strategy. Nor is the U.S. so superior in many areas of technology relevant to strategic defenses and military uses of space that we can expect to establish superiority without a long and hard struggle with the Soviet Union. The second obstacle to the Fossedal-Graham strategy is that it is very far from the center of the present spectrum of U.S. defense policy alternatives. Current U.S. policy guidance, developed by the most conservative, pro-defense administration in many years, favors a cooperative, mutual deploy­ment of space defenses and reduction of offenses. That is, it foresees the move toward strategic defenses as a way to lessen the tension and danger associated with a policy of competitive cooperation with the U.S.S.R., not to overturn that relation­ship and forcibly roll back Soviet influence. Does America have the political will to adopt and sustain an offensive policy?

Professor Jastrow’s strategy, envisioning a mutual, phased deployment of defense and reduc­tion in nuclear offensive weapons, is more in keeping with current U.S. policy guidance on SDI. However, Jastrow and present U.S. policy have not yet given compelling answers to some important issues. The first is that, for a mutual, phased introduction of defenses and reduction of offenses to occur, both the United States and the Soviet Union need to be convinced that a mutual retaliatory policy, and negotiated mutual reduc­tions aiming at the ultimate obsolescence of offensive nuclear weapons would meet (or meet as well as possible) their national security interests. The Soviets have made it clear that they believe offensive nuclear weapons are the decisive weap­ons of war and potent instruments of political intimidation. Their forces and policies appear to be designed to ensure nuclear superiority, in order to prevail in war or peace. Accordingly, they have been unreceptive to U.S. ideas about nuclear balances and ideas of stability, and hostile to U.S. strategic defense. They have tried to halt the SDI research program and have said that they would attempt to counter any strategic defense deployments.

Jastrow argues that the development of effective defenses would convince both sides that building more offensive weapons would be unprofitable. However, the superiority of defenses to offenses might not be obvious enough in all circumstances to persuade the U.S.S.R. to (as opposed to longer-term possibilities) might not exercise this sort of leverage at all.

Furthermore, if Jastrow’s strategy were imple­mented and nuclear weapons did become obsolete, the U.S. would have to fill a major security gap left by the demise of its offensive nuclear weapons. The effective elimination of offensive nuclear weapons could force the U.S. to develop general-purpose forces and plans to deter or defeat aggression wherever and at whatever level it occurred. Indeed, the U.S. may have to face this expensive and unwanted requirement in any case, as extended deterrence becomes less credible and more dangerous. Alternatively, optimists may believe that the elimination of mutual offensive threats and the process of negotiations which would accompany the deployment of defenses would reduce animosities between the United States and the U.S.S.R. and limit the risks of war. Then the responsibilities of U.S. regional and alliance forces would be reduced, and no improve­ments to those forces would be needed.

It is almost certain that the United States will not settle on its ultimate objectives for strategic defense, or the strategy it wants to develop to support those objectives, for some time yet. Differences such as those noted between the Fossedal-Graham and Jastrow approaches need to be addressed and resolved, and other ideas about the long-term objectives of SDI need to be thought through as well. In addition, there are avenues open for U.S. nuclear strategy which would not require strategic defenses.

Two basic approaches rely on offensive weapons alone. Choosing one of these would allow for a continuation of defensive arms control agreements and negotiations of bans on space weapons. The least spectacular approach is to try to maintain current U.S. nuclear strategy. Presently, it is called the countervailing strategy, which is the latest refinement to the flexible response/limited options approach to nuclear strategy which was first adopted by the U.S. in the early 1960s. This strategy has come to accept Mutual Assured Destruction as an underlying condition of large, reasonably survivable nuclear arsenals. As long as the U.S. and the Soviets take necessary precautions, neither one could realistically hope to limit its damage to very low levels following a massive nuclear exchange. As a consequence, the U.S. does not view the threat of all-out nuclear war as a useable policy option, but as a final, passive deterrent. We have instead developed a number of limited nuclear-attack options for our central and regional forces which are potentially less devastating, and therefore more plausible, responses to Soviet aggression. These “limited options,” the chief element of U.S. nuclear strategy for many years, would be used to respond in kind to limited Soviet nuclear attacks on the U.S. and our allies, or perhaps to attempt to halt a massive Soviet assault against NATO, using conventional and perhaps chemical weapons. The U.S. believes these more credible threats would, in the event deterrence should fail, offer some hope of controlling and containing a nuclear war and leading to an acceptable peace.

In the absence of strategic defenses, we might be able to find ways to continue this strategy. To do so, however, would almost certainly require the development and deployment of new gener­ations of improved, more survivable offensive nuclear forces, better target acquisition capa­bilities, military assets to track down and destroy mobile targets, and weapons to destroy very hard and deeply buried facilities. The need to carry out these programs would put narrow limits on acceptable arms-control agreements and compli­cate verification of compliance with the agree­ments that are in principle acceptable. An under­standing of this prospect, along with the technical challenge of developing these forces and the reluctance of political authorities to support them, is one of the most important reasons many strategists have come to support SDI.

The other major approach using only offenses is to give up the plans and forces for conducting limited nuclear options and to rely much more explicitly on the ultimate threat of massive nuclear retaliation for U.S. security. Many people believe that nuclear weapons are a much better deterrent than the proponents of the limited-options approach admit. The threat that in the event of a severe Soviet provocation, the United States might retaliate with several hundred nuclear weapons is so terrible, they argue, that it is adequate by itself to deter almost any aggression. Reverting to a clearer and more direct reliance on this threat, perhaps backed up by stronger nonnuclear forces to defeat minor aggression, is a strategy which is quite widely advocated today. However, adopting this strategy would mean abandoning the limited-options stra­tegic approach which has been repeatedly renewed over the past twenty years. It would mean convincing ourselves that the single threat to retaliate massively can by itself deter large and small-scale aggression against the United States, its friends and allies. This has not been acceptable to U.S. presidents in the past, and it is unlikely to be in the future.

Long before agreement is reached about what long-term U.S. defense objectives and strategy should be, and whether they will or will not require strategic defenses, the administration and Congress will make important decisions about the future of the SDI program. The actual choices that are available for the next few years are narrower than the long-term strategic options and have become quite clear. Continued reliance on an offense-only approach has proven to be increasingly difficult, and for good reasons the United States has chosen to investigate major alternatives.

If the United States continues to pursue SDI research, there are two general near-term courses available. The first is to conduct research and development on strategic defense technologies which would offer a decisive technical and cost advantage over offensive nuclear weapons. If perfected, such weapons would allow for a major and rapid transformation of strategy from reliance on offenses to defenses. Problems with a long, drawn-out transition to defenses, where there are troublesome combinations of offensive and defensive forces on both sides, would be minimized. In the presence of such defensive weapons, both sides would realize that attempting to retain offensive ballistic missiles would be fruitless, and a rapid movement to nearly leak-proof defenses and rudimentary offenses would be assured. This approach is largely consistent with the SDI research program plans for the fiscal years 1985 and 1986 and with recent presidential policy statements on SDI. It would probably require a long period of research and development and no near-term deployments, therefore allow­ing, even encouraging, the continuation of treaty constraints on strategic defenses while research is being conducted. Hard decisions about the utility of actually building and deploying defenses could be put off for many years, and the propriety of deploying such weapons, if they were ever perfected, would be unquestionable. Of course this approach would do nothing to resolve present U.S. strategic problems, and in practice would require either the continuation of the counter­vailing approach or movement toward an offensive strategy more closely resembling MAD.

The other approach is to adapt defenses to something resembling the countervailing strategy, while orienting that strategy toward the incor­poration of more and better defenses as they become available. This would require emphasizing research into less effective but nearer-term technologies, along with longer-term research. Since demands on these defenses would be less, their prospects for success would be greater, and they might be available much sooner. The less-effective defenses which might be developed and deployed in the nearer-term could initially be used to restore and strengthen some variant of present U.S. nuclear strategy by reducing Soviet confidence in their ability to achieve their nuclear-strike objectives. Using defenses in this way would require the U.S. to continue to rely heavily on offensive nuclear forces for some time. Thus the U.S. could continue to threaten the use of limited nuclear options to extend deterrence to our allies and to make credible responses to less-than-all-out Soviet aggression against the United States.

But this departure from a primarily offensive strategy which limits defenses would be a major—and might be an irrevocable—step. To take that step without being sure that we can get to an acceptable strategy, better than the one we now rely on, would be hazardous in the extreme. That is why many serious and responsible strategists and policy-makers have approached SDI with great caution. But as this review has tried to indicate, our understanding of better long-term strategies is not yet complete, and the cases made for most of them are not yet compelling. Because the problems with an offense-only strategy are so pressing, the U.S. may nevertheless feel com­pelled to move ahead with developing and deploy­ing whatever strategic defenses become available. If so, we need to be sure that each step we take leads us to a satisfactory and self-contained stopping point (or at least to a strategy which is better than other available options) before we make the move. We need not only to continue examining where we ultimately want to go with strategic defenses but how they might help us to resolve our strategic problems in the next decade.