Main Page | See live article | Alphabetical index

Anti-Ballistic Missile Treaty

The Anti-Ballistic Missile Treaty (or ABM treaty) was a treaty between the United States of America and the Union of Soviet Socialist Republics on the limitation of the anti-ballistic missile (ABM) systems used in defending areas against missile-delivered nuclear weapons. The treaty was in force for thirty years, from 1972 until 2002. On June 13, 2002, six months after giving the required notice of intent, the U.S. withdrew from the treaty.


The treaty agreed stated that each nation may have only two ABM deployment areas, restricted and located at least 1,300km apart so that they cannot provide a nationwide ABM defense or become the basis for developing one. Therefore each country left unchallenged the capability of the others retaliatory missile forces (see mutual assured destruction).

The ABM systems that may be deployed were limited to 200 interceptors and launchers, 100 at each site (reduced to 100 in total, by agreement, in 1974) and both nations agreed to limit qualitative improvement of their ABM technology. A Standing Consultative Commission (SCC) was created to handle treaty-related compliance and implementation issues.


Throughout the late 1950s and into the 1960s, the United States had been developing a series of missile systems with the ability to shoot down incoming ICBM warheads. During this period the US maintained a lead in the number and sophistication of their delivery systems, and considered the defense of the US as a part of reducing the overall damage inflicted in a full nuclear exchange. As part of this defence, Canada and the US established the North American Air Defense Command (now called NORAD).

By the early 1960s the US research on the Nike Zeus missile system (see Project Nike) had developed to the point where small improvements would allow it to be used as the basis of a "real" ABM system. Work started on a short range, high speed counterpart known as the Sprint to provide defense for the ABM sites themselves. By the mid-1960s both systems showed enough promise to start development of base selection for a nationwide ABM system, then known as Sentinel.

At this point an intense debate broke out in public over the merits of such a system. A number of serious concerns about the technical abilities of the system came to light, many of which reached popular magazines such as Scientific American. At the same time it grew increasingly clear that if the system did work, then the Soviets best course of action was to immediately launch an attack on the US before the system became operational.

As this debate continued, a new development in ICBM technology essentially rendered the points moot. This was the deployment of the MIRV system, allowing a single ICBM missile to deliver several warheads at a time. With this system the USSR could simply overwhelm the ABM defense system with numbers. Upgrading it to counter the additional warheads would cost more than the handful of missiles needed to overwhelm the new system, as the defenders required one rocket per warheard, whereas the attackers could place perhaps 10 warheads on a rocket that was perhaps the same price as the ABM.

At about the same time, the USSR reached strategic parity with the US in terms of ICBM forces. No longer would a war be a matter of the utter destruction of the USSR with the US able to continue on, now both countries would be devastated. This led to the concept of mutually assured destruction, MAD, in which any changes to the strategic balance had to be carefully weighed. ABMs, now ready for use after over a decade of development, seemed to be far too risky – it was better to have no defense than one that might trigger a war.

As relations between the US and USSR warmed in the later years of the 1960s, the US first proposed an ABM treaty in 1967. This proposal was rejected. Following the proposal of the Sentinel and Safeguard decisions on American ABM systems, the SALT I talks began in November 1969. By 1972 agreement had been reached to limiting strategic offensive weapons and strategic defensive systems. It was signed in Moscow May 26, 1972, and ratified by the Senate August 3, 1972. It was seen by many as a key piece in nuclear arms control, being an implicit recognition of the need to protect the nuclear balance by ensuring neither side could ever consider itself immune from retaliation.

For many years the ABM Treaty was considered one of the landmarks in arms limitations. It required two enemies to agree not to deploy a potentially useful weapon, deliberately to maintain the balance of power. In doing so, the formerly terrible relations between the US and USSR started to change considerably.

The treaty was undisturbed until Ronald Reagan announced his Strategic Defense Initiative (SDI) on March 23, 1982. Reagan stated that SDI was "consistent with... the ABM Treaty" and he viewed it as a defensive system that would help reduce the possibility of mutual assured destruction (MAD) becoming reality; he even suggested that the Russians would be given access to the SDI technology, although his advisors soon tempered that idea.

This extremely ambitious project was a blow to Yuri Andropov's tentative 'peace offensive'. Andropov said that "It is time they [Washington] stopped... search[ing] for the best ways of unleashing nuclear war... Engaging in this is not just irresponsible. It is insane".

SDI research went ahead, although it did not achieve the hoped for result. SDI research was cut back following the end of Reagan's presidency, and in 1995 it was reiterated in a presidential joint statement that "missile defense systems may be deployed... [that] will not pose a realistic threat to the strategic nuclear force of the other side and will not be tested to... [create] that capability." This was reaffirmed in 1997.

It was not until George W. Bush gained office that the treaty was back in the political arena. On December 13, 2001, Bush gave Russia notice of the United States' withdrawal from the treaty, in accordance with the clause that requires six months' notice before terminating the pact. This was the first time in recent history the United States has withdrawn from a major international arms treaty.

Supporters of the withdrawal argued that it was necessarily in order to test and build a limited National Missile Defense to protect the United States from nuclear blackmail by a rogue state. The withdrawal had many critics. John Rhinelander, a negotiator of the ABM treaty, predicted that the withdrawal would be a "fatal blow" to the Nuclear Non-Proliferation Treaty and would lead to a "world without effective legal constraints on nuclear proliferation."

Reaction to the withdrawal by both Russia and China was much milder than many had predicted, and followed months of discussion with both Russia and China aimed at convincing both that development of a National Missile Defense was not directed at them. In the case of Russia, the United States has stated that it intends to discuss a massive bilateral reduction in the numbers of nuclear warheads, which would allow Russia to reduce its spending on missiles. In the case of China, statements by Condoleezza Rice, United States National Security Advisor, appeared to some observers to suggest that the United States would not object to an expansion of China's nuclear arsenal in a manner that would allow it to overwhelm American anti-ballistic capabilities.

External link

See also: nuclear disarmament, nuclear warfare, nuclear weapon, Strategic Defense Initiative, National Missile Defense, mutual assured destruction\n