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International Network of Engineers and Scientists Against Proliferation |
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Contribution to 11th Summer Symposium in Shanghai, July 28-August, 1999
If a country is serious to its commitment of not being the first to use nuclear weapons (No-First-Use), it must have physical applications in the ways of the country in developing and operating its nuclear weapons. Such applications are more or less visible to other countries. This study proposes an approach to identify the No-First-Use nuclear strategies by observing the visible evidences of the strategies.
In the debates over No-First-Use, an argument has always been mentioned that is a No-First-Use commitment is not verifiable. Actually, this argument is not true. The verification of the commitment means to detect the violations, i.e., to detect first use of nuclear weapons. It is not as difficult to detect a use of nuclear weapons than to detect a small underground nuclear test — a violation of the Comprehensive Test Ban Treaty (CTBT). So, if we have a treaty on No-First-Use, it will be more verifiable than most other arms control treaties. The problem here in implementing a treaty on No-First-Use is that we may not have early warning of violations if we do not make such arrangements in the verification. Many other arms control treaties, for example, CTBT, have the same problems. The CTBT verification does not have any formal arrangement to detect the preparation of nuclear tests, so its verification systems that had worked did not provide early warning before the Indian nuclear tests last year. The problem of early warning for a No-First-Use treaty may be more serious than other treaties because the consequences of a violation of the No-First-Use treaty are considered to be more serious.
So, it is not a problem at all to make the No-First-Use treaty verifiable. If we want the treaty more acceptable, the problem is to provide early warning of violations so that people have enough time to respond to the violations before they happen. There are two categories of measures that can help serve for this purpose. The first category of measures is to detect the preparation of nuclear weapon launches, for example, to deploy sensors on the tops of missile silos. The methods in this category can be arranged to be reliable but also intrusive.1 This category is not the emphasis of this paper.
The second category of measures is to observe the visible evidences of the No-First-Use nuclear strategy. The methods in this category can not timely find sudden changes of nuclear strategies, but they do not need complicated negotiations to make intrusive verification arrangements. If a country seriously applies its No-First-Use nuclear strategies to the development and operation of its nuclear force, there must be some physical characteristics compatible with the strategies in its nuclear and conventional forces as well. These characteristics include: (1) the size of the nuclear force; (2) the composition; (3) the number of warheads on each missile; (4) the accuracy of nuclear weapons; (5) the strength of the conventional forces. By observing these evidences, people can make judgment how serious a country is to its No-First-Use commitment. One or two of the above characteristics may not provide enough information for making decisive judgment. An observation of more characteristics can help make more persuasive judgment.
If a country uses its nuclear weapons only for retaliation after receiving first nuclear strike, only a fraction of the total nuclear force can work in the retaliation. Some nuclear warheads are lost in suffering from the first strike; some are lost in penetrating the defense of its rival; and the remaining are retaliating warheads. We can compare the number of retaliating warheads with the minimum number of warheads required for producing intolerable damages. This minimum number required was estimated as several hundreds of warheads2 and my estimation is several warheads.3
When the number of retaliating warheads of a country is much smaller than the minimum number required, the country does not have a real retaliatory capability. In this case, a No-First-Use commitment is equivalent to a no-use commitment. The nuclear force this country has at this moment cannot play well the role of nuclear deterrence. So, at the early stage when a country develops its nuclear weapons, its nuclear weapons can make very little positive contribution to its national security immediately. At this stage, the No-First-Use strategy is only a principle that sets the goal of the nuclear development in this country. It does not suggest that the country has had the nuclear retaliatory capability.
When the number of retaliating warheads of a country is much bigger than the minimum number required, it indicates that the country has the plan to use nuclear weapons first in some ways. So, people can identify the No-First-Use nuclear strategies by measuring the sizes of nuclear forces.
Sometimes, strategic nuclear weapons refer to those with long ranges while tactical nuclear weapons refer to those of shorter ranges. For nuclear-weapon-states neighbouring to each other, short-range nuclear weapons can also attack strategic targets if they are used to do so. Tactical nuclear weapons are specially designed for battlefield or theater use. In this case, some weapons can be used for either strategic or tactical purpose. In this paper, tactical nuclear weapons refer to those that are specially designed for use in military conflict in battlefield. They are not so good for the purpose of strategic retaliation. If a country deploys tactical nuclear weapons in its operational nuclear arsenal, it suggests that the country could use nuclear weapons first in some ways. However, there is one exception: a country interprets its No-First-Use commitment as „not to use its nuclear weapons first outside its territory." In other words, the country does not consider the use of nuclear weapons on its territory to prevent a big invasion as „first use." This is a special version of No-First- Use. The existence of certain kinds of tactical nuclear weapons is not incompatible with this version of No-First-Use policy.
Usually, several nuclear warheads are needed to destroy one silo-based nuclear missile. In the best situation, it needs at least one warhead to destroy one silo-based missile. If the missiles of the two fighting sides are all tipped with single-warheads, a pre-emptive strike cannot help either side acquire or enlarge the numerical superiority in nuclear weapons. Multiple Independently-targeting Reentry Vehicles (MIRVs) on silo-based Intercontinental Ballistic Missiles (ICBMs) can change this situation. In principle, a country can loose all of its silo-based MIRVed ICBMs in suffering a pre-emptive strike even though it has the same amount of nuclear warheads as the rival. If MIRVed missiles are not launched before suffering a first strike, more warheads on these missiles will be destroyed than single-warheads. To avoid losing more multiple-warheads, a country has to either use these weapons first or launch them on warning (Launch on Warning, LOW). The existence of MIRVs on vulnerable missiles (e.g., silo-based missiles) indicates the intention of an early use of nuclear weapons: first use or Launch on Warning.
The strategy of Launch on Warning could avoid big loss of MIRVs in suffering a first strike and therefore makes the retaliation more credible. But the strategy of Launch on Warning is risky in initiating first use of nuclear weapons because the weapons on alert are very close to the point of launch.
There are a few exceptions in which a country has to deploy MIRVs although this country may not have the intention to use nuclear weapons first or launch them on warning. The first exception is to utilize MIRVs as countermeasure against missile defense because the defenses may be overwhelmed in a small area when several warheads come together. Another exception is to deploy MIRVs on very survivable delivery systems, for example, Submarine Launched Ballistic Missiles (SLBMs). It is not efficient to attack very survivable missiles even if they are MIRVed.
Very high accuracy of nuclear weapons is important in attacking point targets in first strike or in counterforce retaliatory strike. It is not so useful if the weapons are used for countervalue retaliation. If a country keeps increasing the accuracy of its nuclear weapons even after the circular error probability (CEP) is much less than the lethal radius of the weapons for normal buildings, it suggests that the country has the intention to use the weapons to attack point targets in either first strike or counterforce strike.
Accuracy of nuclear weapons is not so visible to other countries. But if we know which technologies have been applied to increase the accuracy of the nuclear missiles, it may help us guess the accuracy. For example, the accuracy of an ICBM can not be increased within hundreds of meters without the help of military meteorology.
Some countries, like Britain, France, regard their nuclear weapons as their last resort to defend their national security. If a country adopts No-First-Use, instead of „last resort" as its nuclear strategy, it must be confident that it is unnecessary to use nuclear weapons as last resort in defending its national security. In this case, the country must have a not-so-vulnerable conventional force, which can deter all possible large scale attacks except nuclear attacks. If the conventional force of a country is very vulnerable, a no-first-use strategy does not help its national security.
The No-First-Use nuclear strategies may have some other characteristics. By applying the approach described above, the characteristics can also help identify No-First-Use nuclear strategies.
A treaty on No-First-Use does not have problems in verifiability. The problem is to provide early warning for an early response to possible violations. Beside making intrusive arrangements of detecting nuclear weapon launches, people can identify No-First-Use strategies by observing their visible characteristics.
A No-First-Use commitment by all nuclear states has been proposed and pushed for a long time. This commitment, if it is seriously made by all nuclear states, will dramatically change the sizes, compositions, and operational ways of their nuclear forces.
1. Li Bin, "Exploring Visible No-First-Use", paper presented at the 4th Pugwash Workshop on "The Future of the Nuclear Weapon Complexes of Russia and the USA", Moscow and Snezhinsk, Russia, 8-14 September, 1997
2. Harold A. Feiveson et al., „The Nuclear Turning Point", Brookings Institution Press, Washington, D. C. p. 52.
3. Li Bin, „China's Nuclear Disarmament Policy", in „The Nuclear Turning Point." p. 327.
Li Bin is Research Associate, China Youth College for Political Science, Adjunct Associate Professor, Peking University.
Address: Research Division , China Youth College for Political Science, 25 Xisanhuan Beilu, Beijing, 100089, China; tel +86-10-68421144 ext. 5934, fax: -68475470, email: peace01@hotmail.com.
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