Deterrence in a Nuclear Environment



The laws governing deterrence through conventional forces are pretty straight forward. Nuclear weapons by contrast, because of their enormous scale of destruction have a far more complex theory of deterrence. The induction of nuclear weapons in the Indian sub-continent has rendered the old deterrence strategy between Pakistan and India invalid. This article will examine the paradigm shift that has come about in deterrence because of the introduction of nuclear arms in the region.

Definition of Deterrence

Simply put, deterrence aims at preventing the enemy from using his armed forces to impose his will on us. Deterrence aims are exactly the opposite of war aims where force is used to impose one’s will on the enemy.

If deterrence is used simply to prevent an enemy initiating against us an action of which we are afraid, its effect is defensive; if on the other hand it is used to prevent the enemy resisting some action which we propose to take ourselves, deterrence is offensive.

Deterrence may be total if it is applicable to all shades of the use of force or limited if it applies to a portion of the spectrum only. But as soon as it is no longer total é as is generally the case é it becomes necessary to define its precise scope. This leads us to dissect a vital concept, that of the influence of the induction of nuclear weapons in the concept of deterrence.

The Influence of Nuclear Weapons

The use of atomic bombs over Hiroshima and Nagasaki put an end to the age of ‘manufacturing warfare’ and opened the age of ‘scientific – technical warfare’.

The enormous scale of destruction of nuclear weapons means that the use of these weapons was simply no longer practical, either as a normal or exceptional means of policy. On the other hand, the very existence of the terrifying threat of these weapons could be politically exploited either to maintain the status quo or to further the essential changes. With the induction of nuclear weapons we have moved from a war of strategy to a strategy of potential threat; in other words to a strategy of deterrence.

Nuclear Stability

There are various levels of nuclear stability and these deserve careful analysis. Let us take a situation where, for instance, one side has an effective riposte (2nd strike) capability of 90 percent (effective capacity to destroy 90 percent of the enemy) and the other has only 15 percent riposte capability. With a riposte capability of 90 percent, the stronger side has an absolute deterrence against the weaker side whereas the latter has only a defensive deterrent capability, valid merely for self-protection. The stronger side, therefore, can exert an offensive deterrent effect; for instance, prevent the weaker side from reacting against a third party, or even against itself as long as the weaker side’s vital interests are not threatened. The weaker side can also deter and his deterrence will hold as long as the result the aggressor nation is seeking is not worth losing 15% of the aggressor’s total assets. Are the two states then in a situation of mutual deterrence? Destruction of even 15% of the total national assets is a very high price and few states would be willing to pay that price in an offensive role. To that extent, the two states are in a state of mutual deterrence as the weaker one can deter the stronger from a full scale aggression. Can one imagine a conventional force six times inferior to the adversary in absolute terms having a similar deterrent effect on the latter? This phenomenon implies a degree of equilibrium, quite unthinkable with a similar ratio of conventional forces.

The whole edifice of mutual nuclear deterrence rests upon one very simple but vital factor, each side’s fear of finding that the other fires first; for if no one fires first there will be no riposte, but if no one fears that someone will fire first there is no nuclear deterrence. The disappearance of nuclear deterrence would then give rise to the cataclysmic total conventional wars that were witnessed in the first half of the 20th century é for that matter that has plagued the human civilization in one form or the other ever since its recorded history. The problem of first strike credibility is, therefore, anything but a secondary problem. On the contrary, it is the overriding security factor of our era.

Who fires first? Two different scenarios emerge. Take an instance where side A has a marked superiority in conventional weapons over side B and also harbours aggressive designs against it but finds its conventional superiority checkmated by the latter’s defensive nuclear deterrence. Also, side A is superior in nuclear arsenal as well and has an offensive nuclear deterrence but is reluctant to start a conventional war, if it leads to an escalation that may result in a nuclear exchange. It is not willing to pay the price of destruction side Bs nuclear response is likely to cause in reply to its conventional attack even though side A possesses the potential to decimate side B through a nuclear riposte. Neutralization of side B’s nuclear assets then becomes logical if side A decides to resolve its dispute through use of force by using its conventional superiority. Hence, the first strike option for the aggressor, using all means including the use of nuclear weapons to neutralize side B’s riposte capability. This first strike action can only be rationalized if it can be ensured that through it the enemy’s riposte is reduced to a tolerable level. Given the massive destructive capability of even a single atomic bomb, it virtually would amount to near total destruction of side B’s nuclear arsenal. Only when side B’s nuclear deterrence is eliminated can side A afford to pursue his political objective through the use of force. Counter force capability (attack on enemy’s nuclear and conventional forces) would then become the keystone to nuclear deterrence because only that capability, provided it is adequate, can make launching of first strike credible by the stronger nation. The difficulties of achieving an adequate counterforce capability are becoming more and more apparent and its results problematical. These difficulties notwithstanding, the conclusion that counter force capability remains the keystone to total nuclear deterrence remains valid.

Now, let us examine the first strike option of side B, the one which suffers from conventional inferiority, its nuclear deterrence is also smaller and defensive in nature compared to the offensive deterrence of its adversary and which has a credible threat to its security by its stronger and belligerent neighbour. The first conclusion that may be drawn is that side B’s nuclear weapons capability besides being in response to the adversary’s nuclear threat, was most probably developed to offset the conventional superiority of its enemy as well, which, for any number of factors side B is unable to match. The first priority of side B would then be to ensure survivability of its nuclear assets from a pre-emptive strike, in other words, ensuring a credible riposte capability. To achieve that end, it would have to calculate the number and types (fusion/fission) of nuclear bombs it needs in its arsenal together with adequate dispersal and effective delivery means to ensure its retaliatory (second strike) capability remains credible. In addition it cannot forsake the first strike option as an automatic response in certain defined circumstances which essentially means when its vital interests are being compromised through the adversary’s military means or otherwise. For example, if side A is the upper riparian state and side B’s livelihood depends on the flow of river water whose quantity has been guaranteed by international treaty and side A decides to stop the water supply thereby threatening the entire economic structure of side B, side B should be prepared to threaten use of nuclear weapons in a desperate bid to desist side A from its ruinous act. Similarly, if side A launches a conventional military attack on side B and is in a position to overwhelm it, side B’s threat to use its nuclear arsenal as the last resort in the first strike option then becomes inevitable.

Side B’s nuclear arsenal being inferior to side A, its strike strategy has to adopt counter city/value option (attack on enemy’s population centres and civilian infrastructure) as it does not possess the requisite number of weapons and the required delivery accuracy to undertake counter force strategy (attack on the adversary’s military forces and nuclear arsenal). Such a strategy presupposes that it would evoke an annihilating riposte from side A and it would be tantamount to committing suicide. That would be an act of irrationality and the primary thrust of such a strategy would be to convince his adversary that he is capable of acting in an irrational manner involving the destruction of his own people, if pushed beyond a limit. Such a strategy can never be more than a last ditch solution in default of anything else calculated to keep the enemy in doubt, however small that doubt may be. The credibility of a determination to commit suicide may be very small but the risk involved to both the sides is so disproportionately huge that it is likely to remain effective.

Nuclear deterrence, remains in place as long as both the sides conclude that they cannot prevent the other from unleashing its nuclear arsenal. This was the essence of Mutually Assured Destruction (MAD) concept that prevailed practically throughout the cold war period and which is a part of the policy of ‘minimum deterrence’ which weaker nuclear weapons capable states employ against their stronger adversaries. If one party develops an invulnerable shield against the nuclear arsenal of the other through either defensive (National Missile Defence System é NMD) or offensive (guaranteed destruction of enemy’s nuclear weapons through pre-emptive strikes) it would amount to negation of the nuclear deterrence of the other. This makes for a very unstable situation as the stronger side would be sorely tempted to use force rather than diplomacy to resolve all disputes. The world will plunge into the pre- nuclear age era where full scale conventional wars to settle disputes, which nuclear deterrence has so far prevented at least between two nuclear armed nations, would become common. This is the major objection to USA’s star wars concept where they intend to develop and deploy systems that would make continental USA virtually immune from any nuclear attacks. If USA succeeds in developing such a capability, nuclear deterrence of the rest of the world to USA would cease to exist. As the sole superpower, USA’s conduct of its foreign policy has become belligerent and if the nuclear deterrence is also removed, USA’s bellicosity will know no bounds. So far, star wars concept is beyond the scope of present technology and it can only be hoped that as and when future technology makes the star wars concept feasible, the same technology would also make the present nuclear weapons delivery systems far more complex, putting it beyond the reach of the defensive shield envisaged in the star wars concept. For the stability of the world, nuclear deterrence between major powers must remain in place, because in its absence stronger nations would be far more prone to impose their will on others through use of force (war) rather than through diplomacy.

Interplay of Nuclear Deterrence on Conventional Forces

Since the degree of nuclear deterrence may differ considerably depending on the nature of the equilibrium produced by the nuclear forces, the influence of the nuclear level upon conventional forces may be total, partial or non-existent. Even with nuclear deterrence in place, conventional forces are both important and necessary, their role being either to round off nuclear deterrence if it is not complete, or even to replace it if its influence at the conventional level is negligible.

For developing nations like Pakistan which had developed its nuclear deterrence against very heavy odds and stiff opposition of the developed world in order to balance the conventional superiority of a belligerent neighbour, conventional force are absolutely essential to complement the nuclear deterrence. The developed west concedes that the only method of achieving stability in nuclear deterrence is to base it upon independent nuclear forces; they however maintain that the stability provided by nuclear weapons is attainable only between reasonable powers. According to André Beaufre, “Boxes of matches should not be given to children”. Weak conventional forces would lower the nuclear threshold to a dangerously low level leading to great instability. The west is already nervous about the nuclear capability of Pakistan and India as both are looked upon as not very responsible states and if the former has to fall back on the nuclear threat even for minor skirmishes, raising the spectre of a nuclear exchange frequently, both the countries are likely to be declared as not responsible enough to handle nuclear weapons, with serious repercussions, especially for Pakistan.

For nations having a defensive ‘minimum deterrence’ policy, conventional forces with the ability to thwart minor enemy incursions becomes absolutely essential. In its absence, the enemy can mount a swift offensive, capture a minor objective, declare ceasefire and present a fait accompli to the defender, who would then be confronted with an excruciating choice of either accepting the loss or opting to commit mutual suicide. Conventional forces with the ability to react successfully against any conventional aggression by the adversary must complement the nuclear deterrence of such nations.

Impact of Tactical Nuclear Weapons on Overall Deterrence

During the Cold War period the world was a witness to essentially a bi-polar world with USA and USSR counter balancing each other’s might. It was also a period that saw the formulation of various nuclear doctrines and strategies. By late 1950’s the two superpowers had entered the ‘Mutually Assured Destruction (MAD) phase which checkmated either side from pursuing any action detrimental to the vital interest of the other. USA, with its for more robust economy and much higher technical expertise than USSR and facing conventional forces’ inferiority in Europe against the Warsaw Pact nations, was looking for a solution where they could use their superiority in nuclear technology against enemy’s conventional forces in such a limited manner so as not to provoke a full scale nuclear response from the enemy. They came up with the concept of ‘Flexible Response’ which envisages use of low yield nuclear weapons to negate USSR’s superiority in conventional forces in Europe. The planners hoped that small, around 1 Kt power tactical nuclear weapons in the shape of artillery shells/cruise missile warheads or even small bombs dropped by aircraft would permit their usage in a conventional war without it escalating into an all out nuclear exchange. Development and deployment of tactical nuclear weapons proliferated first by USA and USSR and then among the other three nuclear powers é UK, France and China. This concept was not lost on states which had clandestinely developed their nuclear arsenal é Israel, India and Pakistan é where the last two brought their programmes out of the closet in 1998 é they too would either have already developed tactical nukes or are working very hard to attain the capability.

The concept of Flexible Response came under a great deal of scrutiny by various think tanks and strategists. In a number of war games where tactical nuclear weapons were employed, these eventually led to a full scale nuclear exchange. The flexibility of using tactical nuclear weapons with the hope of ending the war quickly and favourably without the attendant risk of escalation to a full scale nuclear exchange turned out to be a mirage. To that extent low yield tactical nuclear weapons did not deliver but it created a different and equally powerful impact.

We have concluded that while nuclear deterrence prevents major conflicts, it does not necessary deter limited scale wars. In fact greater the stability in nuclear deterrence more will be the temptation by both the antagonists to engage in limited intensity conflicts (LICs). A number of such wars have been prosecuted in the later half of the twentieth century. LICs have flourished because of the confidence that these can be contained and if an escalation is feared, ceasefire can be declared before the matter goes out of hand.

One possible effective method of stabilizing and increasing conventional deterrence would be the introduction of low-yield nuclear weapons into the conventional level. Two distinct advantages are likely to accrue: first, by the threat of employment of a new weapon previously untried in battle, complete uncertainty is created as to the tactical result of the battle and therefore to the entire course of a campaign; secondly, the employment of low yield nuclear weapons would create the fear of the possibility or near certainty of escalation on to the strategic nuclear level. The stability achieved at the nuclear level thus gets extended to the conventional level as well.

Induction of low-yield tactical nuclear weapons at the conventional level would appear to be a very attractive option especially for the weaker side. There are some other factors that need to be considered. First, development of tactical nuclear weapons capable of being fired from artillery pieces need technological skills a few notches above what is required to make high yield nuclear weapons. It also requires greater financial investments in the nuclear field. (It is likely that both Pakistan and India have achieved the requisite technological knowledge and made the financial commitment to overcome the twin obstacles). Secondly, integration of tactical, nuclear weapons at the field level would require a very sophisticated and fool-proof command and control mechanism. USA, NATO and to some extent USSR, Britain, France and China may have the expertise to develop and safely incorporate such systems. For Pakistan and India, it would be a monumental challenge and they would be better off keeping these assets under central control rather than deploy them with the field formations.

To sum up, while deterrence at the nuclear level exerts a powerful stabilizing influence in the overall deterrence, this influence extends to the conventional level only at a relatively large scale. In other words it deters full scale conflicts only. Limited Intensity Conflicts are not deterred unless the nuclear and conventional levels are firmly linked by the threat of employment of tactical nuclear weapons in a conventional battle. Only by paying this price é and accepting the risk é can nuclear deterrence be made fully effective at the conventional level.

Nuclear Weapons Calculus

How many nuclear weapons does a country need to ensure nuclear deterrence? The answer would depend on the type of deterrence (offensive/defensive) one is looking for and also on the opponent’s offensive and defensive capabilities. The cold war saw an obscene proliferation of nuclear arms race between USSR and USA, whereas UK, France and China also enhanced their arsenal but not to the same level as the two superpowers. Some believe that for maintenance of a credible minimum deterrence a finite number of nuclear weapons are all that is essential and a nation need not react to every enhancement of the opponent’s nuclear arsenal. In other words, a nuclear arms race can be avoided even if the adversary provokes it by increasing his nuclear capability. Does this assumption hold true? To test it, let us examine how this figure gets affected with changes in the determinants that govern the number of weapons required to maintain a given level of deterrence.

We begin with certain assumptions. First, we are looking for minimum deterrence capability. We further assume that destruction of two enemy cities will meet our minimum deterrence needs and each city would need to be hit with five nuclear bombs, that our delivery means have a 50% probability of successfully penetrating the enemy defences, and finally the enemy has the capability of destroying 50% of our nuclear assets in a pre-emptive first strike. Now with these sets of assumed determinants, the number of weapons needed to ensure minimum deterrence would be:-

Number of bombs required to take out two cities @ 5 per city: 10 bombs

After factoring in enemy’s 50% intercept capability: 20 bombs

Enemy can take out 50% of our force in a pre-emptive strike. 40 bombs

Let us now assume that:

The enemy has enhanced his offensive and defensive capability. Now, he can intercept 90% of our nuclear weapons because of better NMD system. He also has increased his offensive potential through greater number of nuclear weapons with enhanced accuracy and now can take out 90% of our nuclear arsenal in a pre-emptive strike. Now the fresh calculation would be:

Number of bombs required to take out 2 cities @ 5 per city: 10 bombs

After factoring in enemy’s 90% intercept capabilities: 100 bombs

After factoring in 90% of enemy’s riposte capability: 1000 bombs

The calculations have been based on certain assumptions and the high figures have been taken for ease of calculation and to make a point. In an actual case, the increments in the enemy’s offensive and defensive capabilities may not be as large, thus requiring only marginal adjustments in our own nuclear arsenal. It is also possible that the lowering of the deterrence as a result may still keep the figure above the minimum acceptable level we would like to maintain. In that case, it may not necessitate any further enhancement of our nuclear assets. What it does prove however, is that our second strike capability required to maintain a given level of deterrence would be determined not only by our own offensive capability but also by the enemy’s defensive network and his first strike capability. Any increase in either of these factors would necessitate an increase in one’s own offensive potential é or else the level of deterrence will be lowered. If the reduction in the level of deterrence is acceptable, no enhancement in one’s own nuclear capability would be required but if it is not, increase in one’s nuclear arsenal would become inevitable. To assume that if the enemy manages to enhance the effectiveness of his air defence system and/or increases the lethality of his nuclear arsenal, it will not have an adverse impact on our nuclear deterrence would be wrong.


In the study of deterrence, nuclear weapons has introduced new phenomenon, in its scope, trend and procedures. The diversity of vistas it has opened up has led to very complicated theories and conclusions. This article has attempted to explain these ideas in as simple a manner as possible. Some of the major conclusions are:-

The devastative power of nuclear weapons has made conception of open warfare difficult wherever a minimum credibility is attached to their use. It has also resulted in these being viewed not for their employment in war, as is generally the case with all other weapons but that for prevention of war.

Nuclear weapons have led to a fundamental transformation in the character and influence of armament leading to a reversal of concept. Too great stability recreates the danger of war whereas the danger of destruction creates stability.

The essential feature of strategy of deterrence in a nuclear environment lies in the non-employment of nuclear weapons through judicious exploitation of the fact that they exist.

The technical qualities of nuclear weapons are important but their psychological and political impact is so over riding that it outweighs the technical aspect.

lInduction of low yield nuclear weapons at the tactical level can extend the deterrence to the conventional level.

The Author is a Pakistani Air Commodore (Retd) and the central theme of this paper has been adapted from Andre Beaufre’s book “Strategy for tomorrow”.