The ABM Treaty and US NMD

-Kalpana Chittaranjan, Research Assistant, IDSA


The Anti-Ballistic Missile (ABM) Treaty of 1972 had acted as the cornerstone of security and arms control and the centerpiece of strategic arms control between the USA and the former Soviet Union. The treaty aimed at banning nationwide defences against strategic ballistic missiles, by preventing an expensive and dangerous race between defence and offence, thus providing the essential foundation for negotiated limits on offensive strategic arms. Though the search for effective defences against nuclear weapons was never completely abandoned by the USA or the Soviet Union, the ABM Treaty's precisely defined limitations on missile definitions codified the recognition by both sides that the defence technology then available or foreseeable could not provide genuine protection from the awesome destructive power of nuclear weapons. Widespread deployments of missile defences would, instead, only force the other side to increase and improve its offensive forces to overcome them, which would, in turn, touch off a renewed arms competition. Also, the combination of partial missile defences and accurate, quick-strike offensive forces could increase each side's incentive to strike first in an intense crisis, thus heightening the risk of nuclear war. Today, in a post-Cold War scenario, when the Soviet Union no longer exists and the perceived threat by Russia to US national security interests being not as formidable as that of the once-mighty Soviet Union, what role does the ABM Treaty of 1972 play? Is the treaty still the cornerstone of security and arms control, as it once was, or has it become a relic of the Cold War era that will be either discarded or modified by the USA? Before an attempt is made to understand the role of the 1972 ABM Treaty today, it is essential to make a study of the provisions of the treaty and the events that followed its signing.

Main Features of the ABM Treaty

The ABM Treaty was signed on May 26, 1972, after about two-and-a-half years of negotiation, by the United States of America and the Soviet Union and entered into force on October 3 of the same year. The treaty was amended in a protocol in 1974 which entered into force in May 1976.1

The ABM Treaty banned nationwide defences against ballistic missiles and was intended to prevent the development of an offence/defence arms race. The close link between strategic offences and defences was recognised by the signing of the treaty as was the fact that deployment of defences would only encourage increases and improvements in offensive forces in order to overcome them. The treaty was designed to prevent either side from building a nationwide or "territorial" defence against strategic ballistic missiles. This was accomplished through a series of quantitative and qualitative limits on development, testing, and deployment of ABM systems and components. The USA and the Soviet Union were allowed two 100-interceptor ABM sites, one to defend the national capital and the other to defend an intercontinental ballistic missile field (ICBM). The 1974 Protocol reduced the number of permitted sites to one—this could be either the national capital or an ICBM field. While the Soviet Union maintained its single permitted ABM site around Moscow, the US abandoned its Grand Forks, North Dakota site in 1975 because it was judged that the protection provided by its 100 interceptors to the adjacent missile field was not worth the cost of maintaining the system. Each side could change the system location once.

The treaty contained detailed provisions designed to prevent either side from gaining the capability to "break out" from its limitations and deploying a nationwide defence. Strict limits were placed on the deployment of large phased-array radars (LPARs) since these were then the critical guiding eyes of ABM systems. ABM radars could only be deployed at the single permitted site or at agreed ABM test ranges, and new early-warning radars could only be constructed along the periphery of the country and oriented outward. In the same way, since mobile ABMs had an inherent potential for rapid deployment to protect broad areas, the development, testing, and deployment of all sea-based, air based, space-based, and mobile land-based ABM systems and components was banned. Only research on mobile systems and components could be conducted. Under the traditional view of the ABM Treaty, this ban on mobile systems applied equally to both traditional-technology ABMs, such as interceptor missiles and radars, and those based on "other physical principles", such as lasers and particle beams. Such new-technology ABM systems and components could be developed and tested only if they were fixed and land-based but they could not be deployed unless the treaty was amended.

Additionally, the development, testing, and deployment of multiple-warhead or rapidly reloadable ABMs was banned, to protect the limit on ABM firepower implicit in the 100-interceptor limit at the single permitted ABM site. The treaty also prohibited giving non-ABM systems and components (eg., air defence missiles or anti-satellite weapons) an ABM capability, or testing them in an ABM mode. While the treaty only applied to the signatories, neither side was permitted to give ABM systems and components (or the technical descriptions to build them) to other countries or to deploy them outside its national territory. To facilitate verification of these provisions, the treaty prohibited interference with national technical means of verification, which included such intelligence systems as radars and photo-reconnaissance satellites, and barred deliberate concealment to impede verification. The treaty also created a bilateral forum, the Standing Consultative Commission (SCC), which was established on December 21, 1972, to resolve details of implementing the accord, clarifying compliance questions, and discussing possible means of strengthening the treaty.2

The chief US negotiator of the ABM Treaty, Gerard C. Smith, commenting on it in 1987 said that it was "a document of historic significance. It is a comprehensive, precisely drafted contract to govern ABM relations of the superpowers into the unlimited future. For as long as it endures, it rules out a race for defensive missiles which had threatened to be a major new and dangerous form of arms competition."3 However, the ABM Treaty has been the subject of heated debate before, during and after its signing. This debate became even more heated when US President Ronald Reagan proposed the Strategic Defence Initiative (SDI).

Strategic Defence Initiative

The controversial SDI, popularly known as the "Star Wars" system, as has been mentioned, that was introduced in the 1980s by the Reagan Administration again made the ABM Treaty a subject of heated debate both within the USA as well as between the USA and the Soviet Union. Ronald Reagan, as an initiator and ardent proponent of the SDI, announced his speech on the Star Wars programme to the world on March 24, 1983. The SDI had been set out in a 175-page document, brought out by the Heritage Foundation and prepared by the former Director of the US Defence Intelligence Agency, Lt. General Daniel Graham. In it, Graham recommended the setting up of a system of 400 satellites and space platforms which would constantly stay in orbit, equipped with a number of beam weapons capable of destroying Soviet missiles or enemy missiles as soon as they took off and also in all subsequent sections of their trajectory. Such weapons included systems using light beams and lasers operating on fluorinated hydrogen, or using beams of nuclear explosions and directed impulses released by nuclear explosions. In addition, Graham recommended that the Pentagon place into orbit combat satellites capable of destroying Soviet satellites in outer space and deploy ground-based "energy guns" capable of shooting down enemy missiles before they had a chance of reaching the USA.4

Just as the ABM Treaty had been before, during and after its signing, SDI became the subject of intense controversy, by again playing out many of the arguments for and against missile defences that had taken place in the 1960s. While advocates argued that new defences would dramatically reduce the nuclear threat, the critics stated that they would provide no real protection and would intensify the nuclear arms race. According to the SDI advocates, dramatic advances in such areas as infrared sensors, lasers, particle beams, and high-speed computers had created a new situation, which called into question the conclusion that real defence was unachievable, which led to the ABM Treaty. These advocates also cited the then ongoing Soviet ABM and ABM-related programmes as reasons for pursuing a vigorous SDI programme. However, the critics disagreed by arguing that the awesome destructive power of nuclear weapons had not changed and continued to make highly effective defences that the SDI envisaged, an unachievable goal.5 Ardent SDI supporters, most notable among them the former President Reagan, held out the possibility of a perfect or near-perfect defence. Reagan described the SDI as leading to "a shield that missiles could not penetrate—a shield that could protect us from nuclear missiles just as a roof protects a family from rain." After the Moscow Presidential summit, on June 1, 1988, Reagan predicted that SDI "can just make it impossible for missiles to get through the screen."6 Ironically, former Strategic Defence Initiative Organisation (SDIO) Director Lt. General James Abrahamson is quoted as often acknowledging, "Nothing is perfect and there is no such thing as a perfect defense."7 Finally, the critics of SDI had pointed out that due to the incredible destructive power of nuclear weapons, only a near-perfect defence could have actually protected US cities from Soviet attack. A single atomic bomb can devastate a whole city, as had been demonstrated at Hiroshima and Nagasaki. If a city's defence missed even one attacking warhead, it would leave the city in ruins. At that point of time, the Soviet Union had about 10,000 warheads which were capable of reaching the USA, each of which was many times more powerful than the bombs dropped on Japan.

In the USA itself, the SDI had its diehard proponents and opponents amongst the scientists, defence personnel and lay people. Nobody was sure whether the system was feasible and would work the way it had been projected. Besides, the programme was still in the drawing board and laboratory-testing stage. It was an outer-space shield system which was extremely expensive and highly technological, requiring an intricate set of designs and computers. It would have required billions of dollars of Congressional sanction before it could have become fully operational. By the time the Clinton Administration took over, the SDI budget was drastically cut and then withdrawn.

US Threat Perceptions in the Post-Cold War Era

The Secretary of Defence's Report to the President and the Congress (1994) stated, "Today, more than 15 nations have ballistic missiles. By the year 2000, perhaps 20 nations may have them." The report went on to add that "more than 25 countries, many of them adversaries of the United States, possess or may be developing nuclear, chemical or biological weapons."8

A list of perceived potential US adversaries that possess ballistic missiles in the context of nuclear proliferation are Iran, Iraq, North Korea, Libya, Syria and Yemen. This list could be expanded to include Afghanistan, Argentina, Egypt, India, Pakistan and Saudi Arabia in case anti-Western regimes are brought here.9 Some of these states are suspected of either having developed or being in the process of developing nuclear weapons and in the context of proliferation of weapons of mass destruction (WMD), many of them have stockpiles of, or production capacity for, chemical weapons.10 Several are believed to be working on biological weapons, the example of Iraq being the most recent.

Table 1. Three Tiers of Ballistic Missile Proliferators, 199411

First tier: Second tier: Third tier:

Developing indigenous Capable of developing Dependent on

long-range ballistic long-range missiles with foreign-supplied

missiles foreign assistance ballistic missiles

India Argentina Afghanistan

Israel Brazil Algeria

North Korea Egypt Chile

Indonesia Cuba

Iran Libya

Iraq (pre-1991) Pakistan

South Korea Syria

Serbia Yemen

South Africa Iraq (post-1991)


Though a direct threat to the continental United States is not posed as these countries do not have missiles of intercontinental range, they could present a threat to US allies in Europe and the Far East as well as to US forces operating overseas. The capability of sustaining forces for simultaneous involvement in two regional wars on the scale of Operation Desert Storm (eg., in the Persian Gulf and the Korean Peninsula), is the present US strategy postulalate.

While the urgency of addressing the vulnerability of the USA to strategic ballistic missile attack becomes increasingly unacceptable as the 21st century approaches, it varies according to differing threat assessments. National Missile Defence (NMD) supporters are of the view that the ballistic missile threat is real and growing. Potential instability in the former Soviet Union and a growing assertiveness amongst China's leadership, which are current dangers, could lead to accidental or unauthorised missile launches. "Rogue" states like Iran, Iraq, Libya and North Korea could pose future threats and according to the Central Intelligence Agency (CIA), such states are likely to require at least ten to fifteen years to develop strategic-range missiles (5,500 km or more). Acquiring sensitive technologies such as the guidance equipment intercepted en route from Russia to Iraq in November 1995, could, however, shorten the development time. These states could also develop or purchase space-launch vehicles (SLV) which could be converted for military missions or strategic missiles could be bought outright from the former Soviet Union.12

Ballistic Missile Defence

NMD is one of the three components of the US Ballistic Missile Defence programmes designed to deal with the immediate potential threat to the USA, to US allies and some US forces deployed overseas, from short-range ballistic missiles, as well as the future proliferation threat of longer-range ballistic missiles to the continental USA. Theatre Missile Defence (TMD), a component, is theatre defence which seeks to defend the USA and allied forces against short-range ballistic missiles and cruise missiles and is of two types: a set of lower-tier systems that will intercept missile targets at relatively low altitudes in the atmosphere and upper-tier systems that will intercept outside the atmosphere and at greater ranges.13 The other component envisages developing a robust technology base which would enable the deployment of more advanced missile defence systems over time as the threat from ballistic missiles evolves. Thus, funds are being invested in Ballistic Missile Defence Support Technology Programmes, in preparation for the future, in a number of areas which include advanced interceptor and sensor technologies and chemical lasers. Where the NMD system is concerned, the programme involves developing and testing an integrated system to defend the continental USA against ICBMs launched accidentally, or the intentional launch by rogue regimes of medium-range ballistic missiles. The fixed land-based architecture of NMD would incorporate six elements: a ground-based interceptor; ground-based radar; upgraded early warning radars; forward-based X-band radars; a space-based infrared system (SBIRS); and a battle management, command, control and communications (BM/C3) system.14

NMD Architecture

As has been mentioned, a baseline NMD architecture would comprise:

* existing early-warning systems, upgraded as necessary;

* new ground-based radars (GBR) and space and missile tracking system sensors designed to track enemy missiles and distinguish real warheads from decoys;

* kinetic-kill ground-based interceptors (GBI) designed to destroy enemy missiles in space;

* a BM/C3 system to coordinate engagements.

Such an architecture, as currently envisaged15 could be deployed in the 1999-2003 time-frame. A robust defence of the continental USA, Alaska and Hawaii against limited strikes (defined by the Pentagon as 200 warheads or less) would be provided by five to seven sites, each hosting at least 100 GBI.16 Follow-on deployments to upgrade the NMD could include space-based lasers and kinetic-kill systems, which was formerly referred to as "Brilliant Pebbles." "Brilliant Pebbles" is a hangover from the SDI era and is a variant on the concept of space-based ABM rockets, known as "brilliant pebbles," which can quickly provide a cheap and effective defence. The brilliant pebbles concept was so called because the interceptors would be both smaller and smarter than previous interceptor concepts, which were sometimes known as "smart rocks". The basic ideas of brilliant pebbles are quite similar in many respects to the space-based interceptor (SBI) concept that had previously been the planned space weapons for an SDI Phase I defence, as both systems involve thousands of orbiting rocket interceptors designed to home in on enemy missiles and destroy them by direct collision, in the boost and post-boost phases of flight. However, the three primary differences include the pebbles being smaller and cheaper than SBIs; each brilliant pebble would orbit individually, rather than being clustered in groups of 10 on space battle stations, as SBIs would have been; and brilliant pebbles would be equipped with more advanced sensors and computers, allowing them to detect, track and intercept enemy missiles autonomously, without necessarily relying on other tracking satellites or detailed instructions from the ground.17

Recent ABM Treaty Documents

On September 26, 1997, the USA signed important arms control agreements and issued a number of joint and unilateral statements relating to the 1972 ABM Treaty as well as the Strategic Arms Reduction Treaty (START)-II.18 These agreements codified the commitments made by US President Bill Clinton and Russian President Boris Yeltsin at their March 1997 summit in Helsinki.19 With regard to the agreements on the ABM Treaty, the USA and Russia were allowed to deploy higher-velocity TMD systems provided that they are not tested against ballistic missile targets with velocities above 5 km per second or ranges that exceed 3,500 km. It also prohibits each side from developing, testing or deploying space-based TMD interceptors or components based on other physical principles (such as lasers) that can substitute for such interceptors. Besides agreeing to exchange "detailed" information relating to their TMD plans and programmes on an annual basis, the parties to the ABM Treaty agreed not to flight test higher-velocity TMD systems against ballistic missile targets before April 1999; not to deploy TMD systems with interceptor velocities above 5.5 km per second for land-based and air-based systems or 4.5 km per second for sea-based systems; not to test TMD systems against ballistic missile targets equipped with multiple independently targetable entry vehicles (MIRVs) and not to test TMD systems against strategic ballistic missile re-entry vehicles. As regards START-II, the agreements extend the treaty's implementation by five years to 2007 AD and the Presidential commitment made at Helsinki to negotiate a START-III treaty, after START-II enters into force, with a new ceiling of 2,000 to 2,500 warheads at the end of 2007.

The Demarcation Controversy

Earlier, the focal point of controversies with regard to the ABM Treaty had been the demarcation between strategic and theatre defences. In 1972, during the US Senate ratification hearings, John Foster, Director of DOD Defence Research and Engineering had stated that "capabilities to counter strategic ballistic missiles" and "testing in an ABM mode," which were prohibited by the treaty, meant testing against a target with a re-entry speed greater than 2 km per second or at an altitude exceeding 40 km.20 For a long time, this so-called "Foster-box" was widely accepted in the USA as a practical criterion for distinguishing between tests against strategic and non-strategic missile targets, i.e., tests of BMD systems were permitted against targets travelling at an altitude below 40 km with re-entry speeds of less than 2 km per second. Though it was presented to the Senate by Nixon Administration officials during the ratification hearings as an "authoritative representation" of the US policy, it neither became a provision of the ABM Treaty nor was it a formally adopted policy of the USA. The US Congress explicitly required that any changes in the US interpretation of the ABM Treaty had to be considered by the Senate, by the US Defence Authorisation Bill of FY 1994.21

The Clinton Administration proposed in October 1993 at the SCC, in line with the official US policy that a demarcation between strategic and theatre ballistic missile defence systems be based solely on the demonstrated, i.e., the actual tested capability of the systems, that the ABM systems should be defined as a theatre rather than as a strategic defence according to a technical performance criterion—specifically if it were not tested against a target vehicle with a re-entry speed greater than 5 km per second. The payload range of a ballistic missile is closely related to its speed as it re-enters the atmosphere. The speed of 5 km per second for a TMD test target corresponds to a ballistic missile of about 3,000-km range. Such a missile would qualify as intermediate-range (1,000-5,500 km). Non-strategic missiles usually have a range below 1,000 km which corresponds to a re-entry speed of less than 2.9 km per second and most of them have ranges of less than 300 km (1.5 km per second speed). US and Russian strategic missiles have ranges of 8,000-10,000 km and re-entry speeds of 6-7 km per second.22 Critics have pointed out that the deployment of higher-velocity (i.e., above 3 km per second) TMD systems, although permitted, could circumvent the 1972 ABM Treaty.


Former Russian Defence Minister Igor Rodionov had warned several times in 1996-97 that funding problems and bad management were making Russia's nuclear forces dangerously "unmanageable," which was corroborated by the CIA which had claimed in 1997 that antiquated central missile command systems had accidentally gone to full "combat" mode several times since 1991.23 The package of agreements signed in New York on September 26, 1997, needs to be supported if it allows START-II (which presently awaits Russian Duma ratification) to enter into force and preserves the ABM Treaty, both of which are essential to progress in further strategic arms reductions. The US decision to go ahead with the deployment of NMD could lead to modifications to/repudiation of the ABM Treaty. What Robert McNamara, former US Secretary of Defence had stated in 1987, "If the ABM Treaty were terminated, the US will face a spiralling arms race in both defensive and offensive systems, a competition that will seriously jeopardize our national security and will require major increases in the military budget,"24 is still valid.



1. For the text of the ABM Treaty: the Agreed Statements, Common Understandings and Unilateral Statements; and the 1974 Protocol, see W. Stitzle, B. Jasani, and R. Cowen, SIPRI, The ABM Treaty: To Defend or Not to Defend? (Oxford: Oxford University Press, 1987), appendix, pp. 207-13.

2. Arms Control Association, Arms Control and National Security: An Introduction (Washington, D.C.: ACA, 1989) pp. 71-72.

3. Quoted in: The Arms Control Association, Foundation for the Future: The ABM Treaty and National Security (Washington, D.C.: ACA, 1990), p. 21.

4. The Telegraph, December 16, 1986.

5. Arms Control Association, Arms Control and National Security: An Introduction (Washington, D.C: ACA, 1989), p. 76.

6. Quoted in Ibid.

7. Ibid.

8. Quoted in S. Keeny, "The Theater Missile Defence Threat to US Security," Arms Control Today, vol. 24, no. 7, September 1994, p. 4.

9. R.G. Nagler, Ballistic Missile Proliferation: An Emerging Threat (Arlington, Virginia: System Planning Corporation, 1992).

10. S. Fitter, "Ballistic Missiles and Weapons of Mass Destruction: What is the Threat? What Should be Done?," International Security, vol. 16, no. 1, Summer 1991, p. 14.

11. Aaron Karp, Ballistic Missile Proliferation: The Politics and Technics, (Oxford: Oxford University Press, 1996), p. 17.

12. IISS, "National Missile Defence: The US Debate," Strategic Comments, vol. 2, no. 2, March 1996, p. 1.

13. For issues and challenges facing the US TMD system, see Kalpana Chittaranjan, "US and Russian TMD Systems and the ABM Treaty," Strategic Analysis, vol. XXI, no. 10, January 1998, pp. 1455-1466.

14. USIS, "Arms Control Fact Sheet," Electronic Journal, October 1997, p. 34.

15. For 1997 chronology of developments in the NMD sphere, see The Arms Control Reporter: A Chronicle of Treaties, Negotiations, Proposals, Weapons & Policy, 1997, (Massachusetts: IDDS, 1997), pp. 576, E-NMD, 21-28.

16. n. 12, pp. 1-2.

17. n. 3, p. 32.

18. For text of these agreements (relating to the ABM Treaty and START-II), see "New START-II and ABM Treaty Documents," Arms Control Today, vol. 27, no. 6, September 1997, pp. 19-24.

19. For US-Russian Joint Statement Concerning the ABM Treaty, see "Joint Statement of the Helsinki Summit," Arms Control Today, vol. 27, no. 1, March 1997, p. 20.

20. Congressional Record, Senate, August 8, 1972, p. S27231.

21. Keeny, n. 8, p. 7.

22. A. Arbatov, "The ABM Treaty and Theater Ballistic Missile Defence," in SIPRI Yearbook 1995: Armaments, Disarmament and International Security, (Oxford: Oxford Univerity Press, 1995), p. 683. Also, see pp. 690-693 for account of SCC negotiations upto end-1994 and for US and Russian experts' claims that the advanced US TMD system and components would provide them with a substantial strategic ABM capability.

23. IISS, "Nuclear Weapons First in Russia's Defence Policy," Strategic Comments, vol. 4, issue 1, January 1, 1998, p. 1.

24. Quoted in n. 3, p. 115.