Anti-Ballistic Missile (ABM) Treaty
The Anti-Ballistic Missile (ABM) Treaty was a significant arms control agreement signed in 1972 between the United States and the Soviet Union, aimed at limiting missile defense systems. The context for this treaty arose during the Cold War, particularly amid a substantial military buildup by the Soviet Union, which included a large number of accurate intercontinental ballistic missiles (ICBMs) that threatened U.S. security. In response, U.S. defense planners considered developing active defense systems to intercept incoming missiles, marking a shift from passive deterrence to active defense strategies.
The treaty permitted each nation to maintain limited ABM systems around their capitals and one strategic site, ensuring that they could not develop extensive missile defense systems that could undermine mutual deterrence. While the Soviets adhered to the treaty by deploying a system around Moscow, the U.S. faced challenges in fully implementing its own system due to budget constraints. Over time, the treaty facilitated further arms control negotiations and remained in effect until the early 2000s when the U.S. withdrew from it, citing concerns over new threats and the proliferation of ballistic missile technology. The ABM Treaty is often viewed as a pivotal moment in Cold War arms control efforts.
Anti-Ballistic Missile (ABM) Treaty
Significant arms control agreement between the United States and the Soviet Union
Date Signed on May 26, 1972
In a major step toward de-escalating the growing nuclear arms race, the United States and the Soviet Union agreed to limit their ability to deploy a defensive shield against nuclear weapons delivered by missile.
In the late 1960s, the Soviet Union began a massive military buildup in both conventional and nuclear forces. The American lead in nuclear weapons was challenged as the Soviets fielded a vast number of highly accurate intercontinental ballistic missiles (ICBMs). Launched from the Soviet Union, these new ICBMs were accurate enough to hit US ICBMs in their silos, as well as to destroy US command and control facilities in what is known as a decapitation strike. American ICBMs traditionally had been more accurate, but that advantage had disappeared. The increase in Soviet ICBMs represented another threat to US security. While the Soviets relied heavily on ICBMs for their strategic deterrence, the United States had relied on a triad of ICBMs, submarine-launched missiles, and bombers such as the B-52. The growth of the Soviet navy, however, threatened US ballistic missile submarines, and improving Soviet air defenses threatened the ability of bombers to penetrate Soviet airspace.
Faced with a growing Soviet threat, American planners had three options. First, the United States could try to reduce the numbers of enemy nuclear weapons through arms control treaties, but the Soviets were unlikely to give up their advantage without major US concessions. The second option was a massive, and expensive, increase in American ICBMs, attempting to match the Soviets missile for missile. The final option was to defend American soil from Soviet ICBMs, an idea that represented a major shift in US strategic defense.
Up to this point, strategic planners had viewed nuclear defense in passive terms, using the United States’ nuclear arsenal to deter a Soviet attack or organizing civil defense programs to save American lives in the advent of a Soviet nuclear attack. The new active thinking involved developing a weapons system to shoot down or destroy incoming Soviet ICBMs before the Soviet Union could detonate its warheads. Such a system would have other advantages besides saving American lives. Strategists argued that in realizing that a defensive shield would protect the United States from any incoming attack, the Soviet Union might be persuaded to reduce its number of missiles: It would not matter how many ICBMs it had or would build because they could not penetrate the American defensive system. Large numbers of ICBMs would no longer present an advantage.
The Safeguard System
By the early 1970s, the United States had developed a two-tiered, ground-based missile defense system, known as Safeguard, which it hoped would provide the necessary protection both to American cities and to strategic forces. The first tier of Safeguard was a long-range antiballistic missile (ABM) known as the Spartan. Spartan was armed with a high-yield nuclear warhead to destroy incoming ICBMs in the upper reaches of the atmosphere at a maximum range of 465 miles. If any Soviet warheads leaked through the barrage of Spartan missiles, the second tier of the Safeguard system would engage them with a short-range missile called the Sprint. The Sprint was an extremely fast missile armed with a low-yield nuclear warhead capable of intercepting warheads up to 25 miles from its launch site.
Objections and a Treaty
Despite the benefits of ABMs, they did have their critics. Some US citizens were concerned about the detonation of nuclear-armed ABMs above their own cities. A bigger concern, however, was that ABMs threatened to make nuclear war more, rather than less, likely. First, the Soviet Union might be tempted to launch a nuclear attack before an ABM system became operational, realizing that it could not reliably attack the United States after the system went on-line and its numerical advantage disappeared. Second, there was a worry that an ABM system would encourage the United States to attack the Soviet Union, because the deterrent effect of the Soviet nuclear arsenal would be gone. In future disagreements with the Soviets, the United States, protected behind its ABM shield, might feel safe enough to simply eradicate its Soviet enemy, knowing that the Soviets could not retaliate.
With Safeguard hindering other arms control negotiations, in 1972 the United States and the Soviet Union signed the Anti-Ballistic Missile Treaty to limit the scope of ABM systems. Both sides were permitted to field only limited ABM systems. Each country could field an ABM force around its national capital and one strategic site, such as an ICBM field. The two permitted sites had to be at least 1,300 miles apart to prevent the creation of a regional ABM defensive system. Furthermore, radars and missiles used to shoot down aircraft could not be deployed in a way that might create an ad hoc ABM system.
Impact
The Soviets followed the treaty to its full extent, deploying a missile similar to the Spartan (known as the ABM-1 Galosh) around Moscow and an ICBM field. The United States did not follow the treaty to its full extent. Budget cuts after the Vietnam War meant that a Safeguard system was never constructed around Washington, DC. The one Safeguard system that was deployed, around an ICBM field in North Dakota in 1976, was operational for only four months before budget cuts forced it to shut down. The ABM Treaty, itself a major arms control achievement, cleared many obstacles to other arms control deals in the 1970s.
Subsequent Events
By the 1980s, President Ronald Reagan’s Strategic Defense Initiative (SDI), better known as “Star Wars,” caused the United States to reassess its commitment to the ABM Treaty. Nonetheless, the treaty remained in force through the dissolution of the Soviet Union in 1991. In 1997, the United States updated its participation in the treaty by signing an agreement with Russia, Ukraine, Belarus, and Kazakhstan, designating them successor states to the Soviet Union under the treaty. With the proliferation of ballistic missile technology to nations potentially hostile to the United States in the 1990s and early twenty-first century, President George W. Bush, citing concerns over national security from state-sponsored terrorism, withdrew the United States from the ABM Treaty on June 13, 2002.
Bibliography
Garthoff, Raymond L. Policy Versus the Law: The Reinterpretation of the ABM Treaty. Washington, D.C.: Brookings Institution, 1987.
Powaski, Ronald E. Return to Armageddon: The United States and the Nuclear Arms Race, 1981-1999. New York: Oxford University Press, 2000.
Wirtz, James J. Rockets’ Red Glare: Missile Defenses and the Future of World Politics. Boulder, Colo.: Westview Press, 2001.