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Trust & Verify
May 2001


INF Inspections End - Unilateral Verification Continues

By John Russel

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Midnight on 31 May 2001 signals the conclusion of 13 years of on-site verification under the landmark Intermediate-range Nuclear Forces (INF) Treaty, signed in 1987 by the US and the Soviet Union. Continuous monitoring of missile assembly plants at Magna, Utah, in the US, and at Votkinsk in Russia, will end, as will the right to conduct challenge on-site inspections (OSIs). Since the agreement is of indefinite duration, however, each of the parties will continue to verify the other’s compliance unilaterally, using its own national remote monitoring capabilities.

The INF accord was the first agreement to eliminate a whole class of nuclear armed delivery systems, banning all ground-launched ballistic and cruise missiles with ranges between 500–5,500 kilometres, including Russian SS-20s and American Pershing IIs. It also prohibited related launchers, equipment, global support facilities and operating bases, test flights and the future production of INF missiles. However, associated warheads and guidance systems were not banned.

All missiles covered by the treaty were successfully eliminated by May 1991, within the three-year limit specified under the accord. By agreeing to eradicate all INF missiles, rather than setting limits on their numbers, the verification challenge was made significantly easier. Yet, because INF systems are small and extremely mobile, verification needed to be highly intrusive. This became possible when, for the first time in a nuclear arms reduction treaty, the Soviets agreed to on-site verification.

Several different types of on-site verification were envisaged. They would be undertaken, where applicable, in the Soviet Union and the US, as well as in seven East and West European countries where INF were deployed. A Memorandum of Understanding attached to the treaty declared the numbers and locations of all INF missiles, launchers, support equipment and facilities. Baseline inspections were then conducted to confirm the accuracy of the declarations. Elimination inspections were carried out to verify that missiles and associated hardware were destroyed in accordance with the Protocol on Elimination. Finally, ‘close-out’ inspections were instigated to confirm the absence of all INF equipment, support structures and prohibited activity at missile bases and support facilities. The treaty also contained, for the first time, provisions for short-notice challenge inspections of declared sites. The US conducted the penultimate challenge inspection allowed under the treaty in the Baltic Sea enclave of Kaliningrad in early May, following reports that Russia had moved tactical nuclear weapons there.

In addition, the agreement allowed continuous perimeter or portal monitoring of one former INF production facility in each party’s territory in order to confirm the cessation of production. This was included because the Soviets continued to manufacture the SS-25—a road-mobile missile with a range of 6,500 miles, which was not banned, but which had a first stage ‘outwardly similar but not interchangeable’ with that of the SS-20. Monitoring of the Pershing II rocket motor plant in Utah was conducted for reasons of reciprocity rather than necessity.

Another cornerstone of the verification regime is the use of so-called National Technical Means (NTM)—monitoring capabilities under the control of each party. Particularly important in this context is the use of satellite imagery. The treaty prohibits interference with such means. Furthermore, a Special Verification Commission (SVC), comprising representatives of the two sides, provides a forum for addressing compliance concerns and resolving implementation problems.


Inspections under the INF treaty

Baseline inspections to verify the location and number of all declared items.

Elimination inspections to witness the eradication of missiles.

Close-out inspections to confirm that a given missile base or support facility was free of any INF equipment.

Short-notice inspections to alleviate concerns about non-compliance. For the first three years each party was allowed 20 per year, excluding elimination inspections; for the next five years and for the final five years, each party was permitted 15 and 10 per year, respectively.

Portal monitoring of one former INF missile assembly plant on each party’s territory to confirm that INF missile production had ceased.


Implementation: A Success

Although implementation of the treaty could have been complicated by the collapse of the Soviet Union, negotiations in the SVC ensured that Belarus, Kazakhstan and Ukraine, which had INF missiles or related equipment on their territory, all implemented the treaty satisfactorily. Otherwise there were only a few, relatively inconsequential difficulties pertaining to treaty implementation and verification.

In 1988 the US discovered eight defective Pershing 1a missiles (used for training) that it had failed to declare. These were subsequently reported to the Soviets and destroyed. In March 1990, American inspectors declared an ‘ambiguity’ after the Russians refused to allow the use of X-ray equipment to monitor three SS-25s seen leaving the Votkinsk factory. Russia argued that the US equipment was recording images several centimetres larger than permitted and that these could be electronically enhanced, thereby revealing secret design information. Certain technical adjustments were made and the issue was resolved. Also in March 1990, East Germany admitted to possess 24 conventionally armed SS-23 missiles and launchers, which were destroyed by the end of November. A smaller number of SS-23s was also reported and subsequently destroyed in Bulgaria and the Czechoslovakia. Russia argued that the missiles had been transferred before the treaty came into force and that this had gone unreported to its foreign ministry. Finally, in 2001, the Russians accused the US of violating the treaty by using short-range Hera missiles as targets for testing ballistic missile defence systems.

While OSIs generally worked well, the inspectors tended to find themselves overly constrained by the treaty’s procedures. Having been drafted at a time when relations between the two parties were still characterised by suspicion, the accord allowed inspectors little autonomy to resolve simple ambiguities on-site. These rigidities were overcome with experience and the development of personal relationships between the inspectors and the inspected.

Surviving on NTM

While the INF treaty must now survive indefinitely without on-site monitoring and inspections, verification will carry on via NTM. The SVC will also be available to handle compliance questions and could even agree new verification provisions if needed. Portal monitoring of the Votkinsk plant will be maintained under the first Strategic Arms Reduction Treaty (START) of 1991.

Although the achievements of the agreement are impressive, INF represented only a tiny fraction of the nuclear arsenals of the two countries and were of limited strategic significance. The INF verification system, moreover, applied only to missiles, not warheads. Nonetheless, the INF treaty established groundbreaking verification practices and instituted working relationships between erstswhile adversaries which have fostered further co-operation and established a strong basis for the more complex arms control agreements to come.


John Russell is Arms Control and Disarmament Research Assistant at VERTIC, the Verification and Technology Information Centre in London.




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