Introduction.

This paper discusses the limits of defending against ballistic missile attack on targets on American territory and the territory of it allies or coalition partners, and on American military forces deployed abroad. Although the special focus is ballistic missile defense (BMD), one cannot appreciate the potential and limits of BMD without a conceptual framework which defines the issue broadly, namely a framework which examines the concept of defense in military operations. I thus intend to briefly examine three things: (1) the role and limits of defense as seen by major strategists prior to the advent of nuclear weapons; (2) the demise of air and ballistic missile defenses in American nuclear strategy during the Cold War; and (3) changes in the threat since the end of the Cold War which demand a rethinking of the role of BMD. Within that framework, the limits of BMD will be examined.

Given the confines of this paper, the discussion must be selective and suggestive rather than encyclopedic. I aim only at illuminating the limits of defense within the shifting politico-doctrinal-technical trends which are affecting thinking on military strategy and operations as we enter the next century. I also argue for a long overdue effort to thing more deeply and creatively about how to integrate theater and global-strategic operations--and offense and defense--to prevent, deter, dissuade, and defeat current and emerging threats.

The concept of defense prior to the nuclear age.

Carl von Clausewitz devoted chapter six of the eight chapters in his epic work, On War, to a detailed discussion of the concept of defense. He defined defense as ‘the parrying of a blow’ whose characteristic feature was ‘waiting’. The object of defense was ‘preservation’. Defense, he argued, was easier than attack and the defensive form of warfare ‘intrinsically stronger’ than the offensive. Linking defense to politics, he contended that defense could satisfy only negative political objectives (preventing something from happening), and by itself was insufficient for a full campaign plan. Indeed, defense should be used "only so long as weakness compels, and [should] be abandoned as soon as we are strong enough to pursue a positive object."¹

Clausewitz was writing from the perspective of a strategist whose examples are taken from the military experiences of late 18^th and early 19^th century Europe. He explored the implications of defense for land operations involving infantry, cavalry, and artillery in the aftermath of the revolution in warfare wrought by the Napoleonic wars. Yet as is true in so many other places in his writings, his insights transcend the specifics of his discussion.

Defense has been present in warfare from its earliest days, as part of a dialectic in which offense and defense interact continuously. One uses the defense to parry the offense (to return to Clausewitz’s language), waiting for the appropriate moment to transition to the attack. This trinity of defense, transition, and offense defines the most fundamental military problem at both the tactical and strategic levels. Timing is a critical part of the equation. To counter the enemy’s thrust, to explore the enemy’s weaknesses while concealing or protecting your own, to swiftly and confidently transition to a determined attack, to get within the enemy’s guard, to thrust, to disable, and all of this informed by the political objects which led to and guide the encounter and enveloped by the inevitable and unanticipated shifts which accompany the fog of war—this is the heart of military operations.

Within this image, both the offense and the defense have limits. The challenge is to understand and compensate for the limits, to place them in perspective within the wider political milieu that governs war, to play them off against one another, to position oneself properly to engage the enemy, to strike when the time is right. This image of two duelists can be expanded to the operational perspective of large numbers of organized units, employing different modes of attack and defense, facing one another while other units wait in reserve.

The limits of defense within this image can be described in general terms. The initiative is left to the attacker. The attack can overwhelm by surprise, by mass, by careful selection of a weak point to exploit, by circumvention of the defense’s strengths, or simply by taking advantage of the opportunity to press home the attack with imagination, vigor, and determination. There is a widely held sentiment in most militaries that the offense, if aggressively pursued, inevitably will prevail, and that the defense, if allowed to dominate the confrontation, inevitably will fail.

If one expands this image to include the preparations which precede a confrontation, the issues arise of how to strike the balance between defensive and offensive measures, where priorities should lie, how many resources and how much training to devote to each. Resources and time never are unlimited and difficult choices always are present.

There also are psychological and sociological dimensions to consider. The phrase ‘deterrence’ derives from the Latin term deterrere, the same root for ‘terror’. The proper combination of offense and defense, communicated to the adversary ahead of time, can paralyze the enemy’s will. Conversely, an excessively defensive attitude or mood can weaken a nation, politically and militarily. Complacency based on misplaced belief in the superiority of one’s defenses also can lead to inaction, which a skillful adversary can exploit with fatal consequences, through strategic and tactical surprise. Excessive reliance on defense also can contribute to a failure of will at critical junctures in a campaign. "Fortresses forward of and on the flank are advantageous," wrote one of Clausewitz’s most successful and thoughtful admirers, von Moltke the elder. "Behind the front they are often dangerous because they easily induce weak characters to seek protection therein in case of a defeat—where they usually find nothing but destruction."²

The above discussion, while narrowly drawing on Clausewitz, could easily be expanded to the other major writers in the military canon prior to the nuclear age. It is instructive to have this earlier perspective in mind as we begin to discuss national missile defense (NMD) and theater missile defense (TMD) in the nuclear world.

The concept of defense never disappeared in American military thinking during the Cold War, certainly not for non-nuclear operations and to some extent not even in the nuclear realm. But deliberate decisions were made by the political leadership in the 1960s to discontinue development of the elaborate national air defense network that had been constructed in the 1950s to defend against Soviet bomber attack, and not to seriously pursue a defense against Soviet ballistic missiles. Instead, the nation was to rely upon the threat of assured retaliation to deter general war. This concept was codified as mutual assured destruction in the Anti-Ballistic Missile (ABMT) of 1972. The aim of strategic arms control by this point was to stabilize the nuclear balance. There always was a tension whether the ABMT allowed the Soviets to lay the groundwork for rapid breakout if they saw the opportunity and seized it.

From the early 1950s onward, the military strategy of the United States and its allies depended heavily on the threat of massive nuclear retaliation to deter nuclear attack and general war in Europe. Notwithstanding the official shift in the 1960s to the doctrine of flexible response, the escalation ladder to massive retaliation remained the basic denominator in the strategic equation. By this time, discussion of strategic defense, and especially of BMD, had become highly technical, largely divorced form the broader tradition of thinking about defense as an endless dialectic of defense-transition-offense. In this section, I will briefly explore the concepts which accompanied that shift, again with a view to illuminating how the limits of defense were viewed in American strategy.

"There is a basic paradox," Hanson Baldwin wrote in Foreign Affairs in early 1948, in coupling the word ‘defense’ with modern military means and methods." He continued:

The atomic bomb, the long-range plane, the giant missile have demolished so many ‘security’ concepts that defense, measured by any military yardstick, has become chiefly a reflex of retaliation. ‘Defense’ is completely incompatible with the realities of modern warfare, and if it dominates the military thinking of a nation it is a term synonymous with defeat.³

Baldwin’s analysis foreshadowed a trend in thinking about military operations in the shadow of nuclear weapons which was explored in depth by one of the founders of American strategic studies, Bernard Brodie.

As early as 1946, Brodie had formulated one of the most essential strategic concepts of the nuclear age, the notion of secure retaliation. "The first and most vital step in any American security program for the age of atomic bombs," he wrote, "is to take measures to guarantee to ourselves in case of attack the possibility of retaliation in kind.⁴ " This aspect of Brodie’s though never changed. Conjoined to this concept, however, he also argued in 1946 that he was not "for the moment concerned about who will win the next war in which atomic bombs are used. Thus far the chief purpose of our military establishment has been to win wars. From not on its chief purpose must be to avert them. It can have almost no other useful purpose."⁵

By 1959 when, while working at Rand on a project sponsored by the U.S. Air Force, Brodie published Strategy in the Missile Age, he had refined his thinking on the subject. In that work, Brodie explored the revolution in warfare effected by the capability to strike at an enemy’s heartland with air and missile forces carrying nuclear weapons. He discussed the evolution of the belief that the bomber always could get through, the experiences of the strategic air campaigns of World War II, and how this related to traditional concepts of the offense-defense dialectic. He set this discussion in historical context, citing von Clausewitz as the first great figure in modern strategy—a figure he clearly admired. Yet he reluctantly concluded that this mode of strategic analysis which he himself had employed so skillfully earlier in his career—that is to say, analysis combined with a deep study of military history—was no longer worthwhile. "The advent of nuclear weapons," he argued, has called into question "the entire value of past military experience as a guide to the future."⁶

Actually, it was not the nuclear weapons per se which led to this situation, as Brodie goes on to examine, but the growth of large nuclear stockpiles numbering in the thousands with each weapon having a yield far in excess of the 20 kiloton class of weapons used in World War II. During the 1950s, Brodie had come to accept that one could think through offense-defense scenarios against nuclear attack by small inventories of lower-yield weapons, using fairly traditional analytic tools. Mixes of active and passive defenses against bomber and perhaps even ballistic missile attack still made sense in military terms. But with the advent of massive inventories of mega-weapons, no defense, however elaborate, could save a nation or its deployed armed forces from a massive nuclear attack. In the new environment, Brodie concluded, the only function of defense against nuclear attack was to help preserve the deterrent from destruction in a first strike. Basically passive defensive measures—dispersal, alert, mobility, hardening—were appropriate; active defensive measures beyond some minimal effort to not give the enemy a ‘free ride’ (a term Brodie used) were not.

Brodie’s Strategy in the Missile Age was published initially in 1959, and reissued with a new foreword by Brodie in 1964. Those dates bracket the years when American nuclear strategy shifted, largely accomplished in the Kennedy administration under the guidance of Secretary of Defense Robert McNamara. This is not the place to discuss that shift in detail although it is worth noting that we now have readily available a large number of the more important internal policy documents, declassified and gathered in a single volume, demonstrating in great detail the structure and nuances of the debate at the higher levels of American policymaking.⁷

During the early 1960s, President Kennedy and his senior national security advisers explored a number of sensitive issues like the effectiveness of an American first strike on Soviet nuclear forces. They grappled with criteria for cost-effectiveness which, while appearing precise and objective, in reality had the same degree of subjectiveness which always has accompanied operations research and systems analysis when it tries to answer the question, ‘how much is enough?’ Within this broader debate was the issue of how to proceed with BMD.

At this point in the discussion, a brief review of the BMD story is appropriate. The ballistic missile age began in military terms with the launching of the first German V-2s against Britain in September 1944. By that time, strategic bombing was well underway, and the defense had played critical roles, especially the success of British air defenses in the Battle of Britain in 1940, and the V-1 (cruise missile) campaign had commenced in June 1944. More will be said of the V-campaign later.

By 1945 American leaders were aware that Germany had plans for an ICBM capable of reaching New York City if the war had not ended. World War II had demonstrated beyond any doubt that geographic barriers like the English Channel (and even the Atlantic Ocean) did not confer protection in the air age. The advent of nuclear weapons heightened this concern.

America’s exploratory efforts in cruise and ballistic missile technology predated the war, although the German V-weapon campaign obviously increased interest and activity. Operations research had emerged as a new discipline in the war, and from an operations research perspective, the problem of defending against a missile attack represented the same kind of discrete problem as that of defending against air attack (for which there now was considerable data available.). Conceptually, the defense problem could be dissected into functions and phases, e.g.: (1) acquiring good intelligence on the enemy’s air/missile order of battle, infrastructure, technology, and operations doctrine; (2) early warning and detection of attack; (3) having forcers ready to respond on short notice; (4) a secure, effective command and control network; (5) several lines of defense to engage the attacker, beginning with interceptors vectored to engage at as early a point as possible, to terminal defenses; (6) offensive strikes against the attacker’s staging bases, command and control centers, aircraft/missile industries, support depots, and other critical infrastructure; (7) passive measures to blunt the effect of attackers who penetrated the defense: hardening, civil defense, dispersal, deception, mobility, and the like. Critically important in making this work was attention to system architecture and to careful training and preparation.

The British experience had demonstrated how to move from defense against one form of attack to another. For instance, based on advance intelligence on the V-1 threat, the British had developed a plan (Overlord-Diver) for defense against V-1s. This plan was put into effect on 15 June 1944, shortly after the first V-1 attack. There were three lines of defense: fighter aircraft, searchlights and antiaircraft guns, and barrage balloons. During the first month of the V-1 offensive, almost 100 V-1s were launched daily against the greater London area. About 76% of these were successfully destroyed or diverted from hitting London.⁸

The British also had made extensive studies of how to actively defend against the V-2, but given the technology of the day concluded that they could not intercept and destroy V-2s in flight. Thus once the V-2 campaign commenced, the principal allied defense was to attack V-2 launchers. This was not terribly successful, and the civilian population which was suffering from V-2 strikes (given the much shorter warning times) called for greater action. At a particularly desperate point in the campaign, the British were considering extreme measures such as artillery barrages aimed at points in the sky through which the V-2 trajectories were expected to pass. Fortunately, the success of the allied ground offensive in Europe outpaced the political process, and the emergency measures were not put into effect. In March 1945, the last of the 1,115 V-2s, which hit England impacted at Orpington at 4:45 p.m.

The V-weapon campaigns provided valuable data for early postwar planners. They noted, for instance, that the V-1 cruise missile had been adapted to launch from aircraft as well as from the ground. They also noted that the V-2 ballistic missile had been used in a tactical role (e.g., against the Remagen Bridge) as well as strategically against targets in several countries. During the nine-month missile campaign, more than 25,000 V-weapons were successfully launched: some 21,000 V-1s and 4,000 V-2s. In England alone, V-weapons caused more than 30,000 casualties. The Allied teams examining captured German records estimated that the V-weapon projects cost close to $3 billion in then-year dollars. As a point of comparison, the Manhattan Project cost $2 billion.

As American military planners began to examine the new security horizons in the fall of 1945, they were aware of these sorts of facts. They also were extremely attentive to the facts of rapid technological change during the war. Since atomic weapons as then known were far too large for carriage by anything other than the largest bombers, the theoretical problem of defending against nuclear attack against the United States reduced to the problem of defending against heavy bombers. It was lack of resources and political support, not lack of imagination, that handicapped military planning in this regard up to the time the Soviets first tested a nuclear bomb in the fall of 1949.⁹

At the same time, the military pursued a number of studies and development programs on ballistic missiles, albeit at a slow pace until defense budgets rose in the aftermath of the Korean War. Also by the early 1950s, the prospect of new nuclear weapons designs that would produce much higher yield-to-weight ratios was on the horizon. Priorities and funding for research into ballistic missiles and defenses against ballistic missiles rose with the unfolding arms race. By July 1962, a few months before the Cuban missile crisis, the Army successfully test fired a Nike Zeus missile from Kwajalein which came within two kilometers of a dummy warhead from an Atlas ICBM. Had the Nike Zeus been armed with a functioning nuclear weapon, this would have destroyed the ICBM warhead. It was believed by that time that the Soviets were about a year ahead in such activities.¹⁰

In November 1966, McNamara announced that the Soviets were deploying the Galosh ballistic missile defense system. Two months later, McNamara sent President Johnson a detailed memorandum on the issue of procuring and deploying the Nike-X anti-ballistic missile (ABM) system. The JCS recommended deployment. McNamara disagreed, and reviewing his reasons is worthwhile since their logic continues to structure much of the debate today.¹¹

First, McNamara argued, the Soviets would react to an American ABM deployment by increasing their offensive forces. In the resulting offense-defense race, the costs and risks favored the offense, and the risk of Soviet nuclear attack on the U.S. thus would not be decreased. This type of argument later becomes known as cost-effectiveness at the margins, e.g., that the relative cost of adding one unit of offense will be no more than the unit cost of the last unit of defense.¹²

Second, McNamara argued that the time for China (the other threat being considered in the mid-1960s) to develop a significant ICBM force was significantly greater than the time required for the U.S. to detect this fact and to develop and deploy ABMs to counter it. This type of argument is reminiscent of today’s NMD debate against the type of threats explored by the Rumsfeld Commission.¹³

Third, McNamara argued that while protection of U.S. land-based strategic offensive forces against the type of sophisticated missile attack the Soviets may be able to mount in the late 1960s might prove to be worthwhile, it was premature in early 1967 to produce and deploy Nike-X for that purpose until we had a better understanding of the technology and until we had seen whether arms control might stabilize the threat. This dynamic of linking procurement and deployment decisions and the pace of a program to the evolution of the offensive threat and the dynamics of seeking political solutions continues to overhang the NMD and TMD debates.

The rest of the BMD story through the end of the Cold War, while fascinating in its own right, is tangential to the main thrust of this paper and thus will not be explored. What the above discussion points to is the policy context within which the limits of defense were conceived. Technical milestones, cost-effectiveness criteria, threat assessment, arms control, and the like structured the debate. The U.S. briefly deployed the Safeguard ABM system in 1976. It was operational for four months before Congress directed that it be shut down and that the Army redirect its missile defense program to research and development (R&D) to hedge against a possible Soviet breakout from the ABMT. Two important deficiencies led to this decision. First, the large phased-array radars were vulnerable to Soviet missile attack, and without them the system could not function. And second, the Sprint and Spartan interceptor missiles were armed with nuclear weapons. Once they were first employed, they would blind the system for further engagements. Not specifically cited, but in the background of the decision, was the uneasiness associated with defenses armed with nuclear weapons on alert. The challenge to command and control was significant, and the issue of whether pre-delegated authority would be needed always was in the background of the debates. After the shutdown of Safeguard, the Army turned its R&D effort to a search for non-nuclear defense alternatives such as kinetic hit-to-kill and lasers.

While the U.S. moved away from active defenses, it vigorously pursued passive defenses to preserve the deterrent and the use of offensive measures to suppress the enemy’s defenses. America led the world in electronic countermeasures and stealth technology. It developed a triad of forces in which the deficiencies in survival of any one element would be compensated by the presence of the others. The American Fleet Ballistic Missile (FBM) force gained survival through mobility and stealth. The bomber force was on alert and adopted tactics and technologies to penetrate Soviet air defenses. The ICBM force initially was thought secure in hardened silos, but later became vulnerable to Soviet ballistic missiles. The decision was not made to invest in other forms of survivability like mobility or various other basing schemes. What made American nuclear deterrence credible, apart from the question of political will, was the overall synergism. There were offensive forces trained and exercised to a high state of readiness. There was an elaborate warning and command and control network. The planning process was deliberate and robust. To attack the American deterrent, one had to defeat the system. This system continuously was evaluated for weaknesses and, where found, corrective measures were taken.

Thus, mutual assured destruction, crisis stability, and the desire to avoid unnecessary arms races were at the center of American nuclear doctrine. Added to this, the ABMT became a political factor in the policy equation, beyond simply the terms of the agreement. America’s relations with other countries and the White House’s relation with Congress were part of that equation. This collection of factors—military, technical, financial, political—structured the offense-defense debate in such a way that nuclear strategy became largely disconnected from other forms of military strategy, and active defenses against air/missile attack faded into the background in American doctrine. That is not a good precedent for the world, which followed the end of the Cold War.

What has changed since the collapse of the Soviet Union in the early 1990s? The world has moved from a bipolar to a multipolar structure in which the U.S. is the only superpower. Proliferation of WMD and advanced delivery systems has expanded dramatically, changing the American threat perspective for nations like North Korea, Iran, Iraq, Syria, Libya, and others. Transnational terrorism is more sophisticated and may begin to exploit WMD. Russia continues on a slow trajectory of reform toward an uncertain future, while retaining an enormous nuclear arsenal which, while eroding in force readiness, still poses a mortal threat to any country against which it is used, and which factors more heavily in Russian defense thinking than it did even during the Cold War. China also is on an uncertain trajectory, and while its nuclear forces remain modest, they are modernizing at a steady pace. Nuclear weapons have moved from the center of American strategy, and while they continue to maintain an important deterrent and hedging role, the health of the American nuclear infrastructure is problematic.¹⁴

Anyone familiar with contemporary strategic studies literature could continue the above discussion. What is missing from the debate thus far, however, is a sense of the imperative need to correct the disconnects between strategic and theater warfare and between nuclear offense and defense which are legacies of the Cold War. The type of war the U.S. prepared for during the confrontation with the Soviet Union is the one within which the limits of BMD traditionally were evaluated. This was a general war beginning with Soviet aggression in Central Europe and escalating quickly to a nuclear phase which, if not controlled (and escalation control always was a problematic concept) would quickly cascade to general nuclear war. Today, we are faced with different sorts of models. There are two I will develop briefly, as a backdrop to discussing how to envision the limits of BMD in today’s emerging world.

The first model is that of a regional contingency where we are faced with an adversary that is much weaker conventionally than any coalition of forces based around American expeditionary power (although he may have other offsetting advantages), but that has WMD and advanced delivery systems. Such a nation may have a nuclear inventory numbering in the tens or so, with the options for air, ballistic missile, or unconventional delivery schemes. This is somewhat analogous to the Soviet threat we faced in the early 1950s. Its chemical (CW) and biological (BW) weapons programs are likely to be much larger. American’s counter-proliferation (CP) policies of the past few years have been build around such presumptions. The motivations for such regional aggressors to acquire WMD depend on a number of factors, one of which is the desire for asymmetric response options to influence American decisionmaking.

A regional contingency is likely to involve a melange of conventional operations, information operations (IO), and WMD. Ballistic missiles in the hands of the regional aggressor give him the option of escalating the conflict outside the regions. If he strikes capitals of coalition partners or threatens the United States itself, the regional contingency clearly has reached strategic proportions. In fact, it is not difficult to conceive of scenarios in which this also gives him the change to trigger a war which expands outside the region.

This is a model where we need to better understand how to integrate offensive and defensive operations (including information warfare), and theater and strategic campaign plans. Such understanding is crucial if we are to assure that we organize, plan, and train our forces properly. I believe, although there is not space to develop the argument in detail in this paper, that the classic manner of thinking about the defense-transition-offense dialectic applies to this model, and that fighting will not end with the first use of WMD. The challenge to military planners is to integrate their understanding of: (1) long-range precision strike conducted in a non-WMD mode; (2) other ground, air, and naval operations conducted in a non-WMD mode; (3) CP operations if and when the enemy uses WMD; (4) IO operations throughout; (5) and active and passive defenses, including active TMD and NMD. American nuclear weapons will likely figure in this equation as a deterrent to WMD, although it still is far from clear what that entails. American plans and postures should be designed to raise the WMD threshold for the enemy, to reinforce deterrence at all phases of the conflict, and to seek to cast the deterrent shadow as early into the scenario as possible.

The second model I have in mind is a new peer competition at much larger numbers of nuclear weapons than in the first model. The two countries most likely to fit this model are Russia and China. It does not replicate the Cold War confrontation, but it does raise a different set of offense-defense questions than in the first model. With this framework in mind, it now is possible to return to the question of the limits of defense, especially of BMD.

How would the adversary counter TMD or NMD? He may attack key nodes in our defensive systems, e.g., seeking through high-altitude nuclear bursts to disrupt warning and command and control. He will probe for other weaknesses in the system, e.g., the lack of boost-phase defenses, and pursue countermeasures accordingly. He will likely be cognizant of the political constraints placed on American options by the ABMT and the political problems associated with placing weapons in space, and will seek to turn those inhibitions in his favor wherever possible. He may supplement his ballistic missile capabilities with other forms of delivery, including non-traditional forms which may prove quite compatible with his military culture and experiences.

The limits on BMD will continue to derive from the military, technical, financial, and political sorts of considerations discussed earlier, but how we approach the questions of integrated offense-defense doctrine and benchmarks for how much is enough can in fact change. One can conceive of NMD and TMD capabilities capable of blunting the regional and potential Chinese threats that do not violate the test of cost-effectiveness at the margins, so long as we confine the analysis to ballistic missiles. Whether they would be sufficiently robust turns on a number of issues, not the least of which is whether they include some form of boost-phase attack. The question is whether the enemy will circumvent NMD and TMD by other attack options, and whether in turn we seek defenses to counter those options. As for the potential Russian threat, a different dynamic is at play. We probably have the resources and technical competence in the near term to do something we could not do during the Cold War, namely, mount an effective BMD against the Russian Federation and win the ensuing arms race, if we were willing to accept the destabilizing consequences of departing from the current assured deterrence relationship. I for one do not think this is advisable. What we can properly be concerned about without violating traditional criteria of stability is an NMD/TMD posture which deals with small subsets of the Russian nuclear force which might spin out of control of the center.

We have entered a world quite different from that of the Cold War, a world for which we are not prepared strategically when it comes to thinking about the role of defense in strategy. This paper has briefly sketched, chronologically and conceptually, some of the parameters of the debate on how to link defense to offense. Defense has limits, but so does offense. What we need to understand is how to offset one with the other where appropriate, ensuring that the defense-transition-offense dialectic which was part of the classical discussion of military strategy now also can inform the continuing debate over BMD.

HOME PAGE