Kahn's Escalation Ladder
The particular ladder we will use has forty-four rungs. It is bordered by a pre-escalation stage called "Disagreement—Cold War," and a post-escalation stage called "Aftermaths." Methodologically, the ladder can be considered a scenario generator that connects subcrisis disagreements or incidents of the Cold War with some kind of aftermath.
The forty-four rungs of the ladder have been grouped into seven units (including varying numbers of rungs)
Another metaphor as useful as the escalation ladder would be that of an elevator stopping at various floors. We can think of a typical escalation situation between the United States and the Soviet Union in terms of a department store with seven floors, each offering a number of options of varying intensity, but still appropriate to that floor, from which the decision-makers on one side or the other may choose.
- 1 Subcrisis Maneuvering
- 2 Traditional Crises (the Boat Is Rocked)
- 3 Intense Crises
- 4 Bizarre Crises (Nuclear Weapons Are Used)
- 5 Exemplary Central Attacks (Violating The Central Sanctuary — Nuclear Gunboat Diplomacy)
- 6 Military Central Wars (the "new" kind Of all-out War)
- 7 Civilian Central Wars (violation of The "no-city" Threshold)
We are interested here not in day-today maneuvers that do not raise the possibility of escalation, but only in the ones that manipulate, either deliberately or otherwise, the fear of escalation or eruption. It will be one of my theses that remote as the middle and upper rungs of the escalation ladder may seem, they often cast a long shadow before them and can greatly influence events well below the violence threshold, or even below that point in a conflict when the explicit threat of violence is voiced.
- Ostensible Crisis
- Political, Economic and Diplomatic Gestures
- Solemn and Formal Declarations
At this stage, the language of crisis is used, but with some degree of pretense. Either one or both sides assert, more or less openly and explicitly but not quite believably, that unless the dispute is quickly resolved, rungs of the escalation ladder will be climbed.
Legal but inconveniencing, unfair, unfriendly, discourteous, inequitable, or threatening acts are carried out against the opponent to punish, apply pressure, or convey messages. If this becomes very hostile, these acts are called "retortions"
These are purely verbal but explicitly solemn and formal actions intended to demonstrate resolve and committal. They may be in the form of legislative resolutions, formal executive announcements, diplomatic notes, or other very explicit and obviously serious declarations. Such a resolution or proclamation may be a simple notice to other nations of one's policy in a certain geographical or other area, or it may address a conflict or dispute more directly. It may often be thought of as a pre-emptive or preventive escalation that tries to forestall escalation by the opponent.
Traditional Crises (the Boat Is Rocked)
In a thermonuclear balance of terror, both nations will be reluctant to start a crisis that could escalate, perhaps inadvertently, possibly even going beyond control and erupting into an all-out war. There is, therefore, a tendency not to let even a low-level crisis start—a constraint not to rock the nuclear boat.
- Hardening of Positions -- Confrontation of Wills
- Show of Force
- Significant Mobilization
- "Legal" Harassment -- Retortions
- Harassing Acts of Violence
- Dramatic Military Confrontations
When the situation becomes coercive rather than contractual, the antagonists often attempt to increase the credibility of their commitments by "bridge-burning" acts, a deliberate increasing of the stakes, perhaps a joining together of several issues with the deliberate purpose of making it harder for the other side to believe that one can be made to back down.
One side or the other may hint, or even make clear, that violence is "thinkable." If it does this by acts rather than words, we call it a "show of force."
The accompaniment of a show of force by a modest mobilization that not only increases one's strength but also indicates a willingness to call on more force or to accelerate the arms race if necessary.
One can harass the opponent's prestige, property, or people legally. That is to say, one may act in a very hostile and provocative manner, but within the limits of international law.
If the crisis is still not resolved, more or less illegal acts of violence or other incidents designed to harass, confuse, exhaust, violate, discredit, frighten, and otherwise harm, weaken, or demoralize the opponent or his allies and friends may be carried out through clandestine or unattributed channels, or through limited paramilitary or other overt agencies.
If there is a direct ("eyeball to eyeball") confrontation that appears to be a stark test of nerves, committal, resolve, or recklessness, all participants and observers will take an intense interest in the proceedings.
I use the term "intense crisis" to mark a crisis in which a significant number of people actually envisage that nuclear war may really occur, yet nuclear weapons have not yet been employed. Of course, there are many who understand abstractly that nuclear weapons exist and may be used, but in this kind of intense crisis the nuclear incredulity that all of us share would be sharply decreased if not eliminated. The "unreal and hypothetical" nuclear stockpiles that exist would suddenly represent a real threat. This change probably would not come all at once, and it might be a limited development; but a part of the population and most of the decision-makers would acknowledge that a nuclear war might take place—that it was no longer either "unthinkable" or "impossible."
- Provocative Breaking off of Diplomatic Relations
- Super-Ready Status
- Large Conventional War (or Actions)
- Large Compound Escalation
- Declaration of Limited Conventional War
- Barely Nuclear War
- Nuclear "Ultimatums"
- Limited Evaluations (20%)
- Spectacular Show or Demonstration of Force
- "Justifiable" Counterforce Attack
- "Peaceful" World-Wide Embargo or Blockade
The escalatory character of this rung is difficult to estimate a priori because, even more than with most rungs, much depends on the circumstances of this diplomatic break. However, I would provisionally suggest that a provocative withdrawal of diplomatic relations would be just past the nuclear-incredulity threshold. After all, this act is a traditional notification that two nations are nearing war. It is a fairly persuasive communication that one nation does not intend to coexist on normal terms with another, and that something further is likely to happen before the crisis is settled. If the break were accomplished in a sufficiently provocative and dramatic manner, it probably would lead to some of the subsequent actions of intense crisis. On the other hand, a diplomatic break with Russia of the kind sometimes advocated by some right-wing groups in the United States might simply be considered a foolish or frivolous gesture, in some circumstances an indication of a lack of seriousness, rather than of seriousness.
A "ready" status may be partial or total. The present handling of SAC is an instance of partialready status. It may be regarded as a routine precaution rather than as the highest point that escalation has reached between the U.S. and the U.S.S.R. However, Soviet-American tension is a necessary political background for partial-ready status, and the status has come about by accumulation. Ten years or so ago, a great deal of criticism would have been leveled against the idea of maintaining strategic forces with ready triggers, but now there is hardly any, at least in the United States.
The stage has now been set for some kind of organized military violence. It may be relatively large-scale undeclared war or border fighting such as what occurred between the Japanese and the Soviets in 1939 (involving thousands of soldiers), a Trieste-type occupation of disputed territory, or a major "police action," as in Korea.
If such a war is fought with any intensity, both sides suffer casualties in large numbers, but neither will use their more "efficient" or "quality" weapons—the nuclear, bacteriological, or chemical weapons. Paradoxically, the more "useful" these weapons are in the narrow military sense, the less likely they are to be used. In any case, there would be many casualties at this rung and, at least in the initial stages of the action, a significant deepening of the crisis.
One way to achieve a high over-all level of escalation and still keep each separate act as an act relatively low on the ladder is to retaliate or escalate in a completely different theater from the one in which the primary conflict is being waged, and at a time when the primary crisis is at a fairly intense level. This may be especially escalatory if the second theater is sensitive or potentially vital.
Nearly all commentators on this subject, and to some degree the U.S. Government, agree that if limited wars have to be fought it is best to fight them with conventional weapons, and that it is unwise to try to improve deterrence by increasing the likelihood that nuclear weapons will be used. Currently, the United States tends to fight limited conventional actions in the guise of "police" actions or by employing advisory groups. These devices make it easier for the U.S. to resist or neutralize domestic pressures to escalate: police actions are normally limited. We do not usually furnish police even with tanks or planes.
During a conventional warlike act (Rung 12) or the super-ready status (Rung 11), one or more nuclear weapons may be used unintentionally (accidentally or unauthorizedly). Or one of the antagonists may make military or political use of a nuclear weapon but try to give the impression that the use was unintentional.
Whether or not there is a conventional or barely nuclear war, the crisis could enter a stage of such increased intensity that the state of nuclear incredulity would not merely be weakened but would vanish. This could occur when one side or the other seriously considered the possibility of a central war and communicated this fact convincingly to its opponent.
This would most likely be at least a quasi-official move ordered by a government for either bargaining or prudential reasons, or both. The difficulties, and possible public and political reactions, make such an evacuation a momentous decision, and one whose consequences could not reliably be predicted. I would also include at this rung serious efforts by one or both sides to prepare for both largescale evacuation and improvised protection.
A spectacular show or demonstration of force would involve using major weapons in a way that did no obvious damage, but appeared determined, menacing, or reckless. The purpose would be to punish the enemy for a previous act, or pre-emptively to punish him for an anticipated one (with the intention of establishing a precedent to deter later provocations), or to intensify the fear of war in the hope of frightening the enemy into backing down.
A "justifiable" attack would be sufficiently specialized and limited to seem a reasonable response to provocation, and yet it might significantly, or even decisively, degrade the military capability, prestige, or morale of the opponent.
This would be an extreme measure of nonviolent coercion brought to bear against an opponent. It is more escalatory than the previous rungs because of its continuing nature.
Bizarre Crises (Nuclear Weapons Are Used)
Up to this point, while nuclear incredulity would have been shattered, nuclear weapons would not have been used extensively. Even if the barely nuclear war had occurred, it presumably would have been accepted as an accident or limited episode, and even a nuclear show of force or "justifiable" counterforce attack might have been understood as a limited action rather than serious nuclear warfare. Now we move wholly into what many consider an entirely bizarre range of possibilities, the very limited and restrained use of nuclear weapons.
- Local Nuclear War -- Exemplary
- Declaration of Limited Nuclear War
- Local Nuclear War -- Military
- Unusual, Provocative and Significant Countermeasures
- Evacuation (70%)
Almost every analyst now agrees that, with the possible exception of Rung 19-type tactics, the first use of nuclear weapons—even against military targets —is likely to be less for the purpose of destroying the other side's military forces or of handicapping its operations than for redressive, warning, bargaining, punitive, fining, or deterrence purposes. As this would be the first unmistakably deliberate use of these weapons since World War II, it would be a profoundly consequential act, even if very limited and specialized.
At this point, it might be judged desirable to make a formal declaration of limited nuclear war—perhaps in hope of setting out relatively exact limits and establishing expectations about the types of nuclear action that the declarer intends to initiate and that he is prepared to countenance from the enemy without escalating further himself.
It is also possible that nuclear weapons could be used in a local situation for traditional military purposes such as defense, denial, destruction, or degradation of the opponent's capability, and so on, and that, within the established limits, the scale and targeting would be, and would be acknowledged to be, dictated by wholly military and "tactical" considerations.
One side might carry out redeployments or maneuvers that would have the effect of shifting the balance of power by increasing an opponent's vulnerability to attack or otherwise degrading its capability, morale, or will.
At this point, the situation may be very close to large-scale war. It may now seem advisable to evacuate a large number of people from cities. The total would probably amount to between two-thirds and threefourths of the population—women and children and those men who are not essential to the functioning of the cities. I would judge that all important industries, communications, transportation facilities, etc., could be operated by about a quarter of the population or less.
Exemplary Central Attacks (Violating The Central Sanctuary — Nuclear Gunboat Diplomacy)
Attacks that avoid the zone of interior of the enemy observe a salient threshold: the one dividing the categories of "homeland" and "not-homeland." To cross this threshold would open the way to large-scale violence.
- Demonstration Attack on Zone of Interior
- Exemplary Attack on Military
- Exemplary Attacks Against Property
- Exemplary Attacks on Population
- Complete Evacuation (95%)
- Reciprocal Reprisals
A "harmless" attack (perhaps on an isolated mountain top or empty desert) which does dramatic and unmistakable physical damage, if only to the topography.
One side might begin destroying portions of the other side's weapons systems, but in a relatively careful way so as not to cause much collateral damage. These attacks could be launched primarily to exert psychological pressure or to reduce the defender's military capability significantly by finding leverage targets.
The next step would obviously be to increase the level of these limited strategic attacks. One possibility would be attacks on such expensive installations as bridges, dams, or gaseous diffusion plants. More damaging and dangerous would be limited attacks on cities, presumably after warning had been delivered and the cities evacuated; the purpose would be to destroy property, not people.
In any crisis of the mid-1960's, this attack would probably be much higher on the ladder than I put it here, but if the balance of terror becomes sufficiently stable, and governments are believed to be under intense and graduated mutual deterrents, even this attack could occur without an eruption to spasm or other central war.
But at this point, large-scale warfare has either begun or is imminent. If at all possible, each side is likely to evacuate its cities almost completely, leaving 5-10 per cent of the population behind for essential activities.
This is a war of almost pure resolve, with more or less continual tit-for-tat exchanges, whether limited to purely symbolic attacks or more destructive exemplary attacks. Many strategists believe that reciprocal reprisal wars— "resolve against resolve"—might be a standard tactic of the future when the balance of terror is judged, whether correctly or not, to be almost absolute or when, because of strategic invulnerability, no other choices are available to desperate or gambling decisionmakers.
Military Central Wars (the "new" kind Of all-out War)
Two groups of central-war rungs lie above the traditional threshold between war and peace (a distinction that has not been obliterated by new developments). In military central wars, the military authorities, or commanders in chief, have access to all the resources of the nation, although their intention is to utilize tactics that avoid or limit damage to an opponent's civilians.
- Formal Declaration of "General" War
- Slow-Motion Counter-"Property" War
- Slow-Motion Counterforce War
- Constrained Force-Reduction Salvo
- Constrained Disarming Attack
- Counterforce-with-Avoidance Attack
- Unmodified Counterforce Attack
An esoteric possibility, almost completely overlooked in modern defense planning, is that one side will respond to provocation with a formal declaration of war but without immediate acts of large-scale violence. An ultimatum or declaration of war might, as in World War II, be followed by a "phony war" period, in which there was some limited tactical or strategic harassment but no large attacks.
In this attack, each side destroys the other's property in tit-for-tat fashion. We sometimes refer to this as a "war of resolve," since each side is attempting to force the other side to back down and there is a naked matching of resolve against resolve. If the exchanges are few in number, and for limited purposes, we call them "reciprocal reprisals" (see Rung 31).
This is a campaign (which could either precede or follow a large counterforce attack) in which each side attempts attrition of the other side's weapons systems over time. One can conceive of a slow-motion counterforce war lasting for weeks or months during which Polaris submarines are hunted down, hidden missiles found, land bases dug up, and so on.
The attacker here attempts to destroy a significant but small portion of the defender's force in a single strike while avoiding undesired collateral damage. It is especially likely to be used against weak links or high-leverage targets at the outbreak of a war.
One of the major arguments for the counterforce-with-avoidance attack (see Rung 37) is that not much is lost by narrow military calculations, and with populations spared, the possibility that post-attack blackmail would work is increased enormously. In the constrained disarming attack, one may follow the same logic further. Tremendous military disadvantages might be accepted in order to spare people and improve the possibilities of successful negotiation to determine the war on an acceptable basis. In this attack, the attacker tries to destroy a significant portion of the defender's first-strike forces and even some of his second-strike forces, but avoids civilian targets as much as possible. This might make it disadvantageous for the defender to launch a counterstrike, since his damaged forces might be only partially effective, even in countervalue targeting, while his attacker might be able to deliver an annihilating second blow against the enemy population with his withheld and regrouped forces.
This attack differs from a constrained disarming attack in that it is less scrupulous about avoiding collateral damage to cities and does not deliberately spare much, if any, of the enemy's second-strike forces. This counterforce attack targets everything that does not involve major collateral damage to civilians. In the case of a Soviet strike against the United States, such an attack probably would include hitting Tucson (a city of 250,000 population, completely ringed with Titans), but probably would avoid the San Diego Naval Base, the Norfolk Navy Yard, and the Pentagon in Washington. If it did hit these targets, or the SAC bases near very large cities, 20-kiloton rather than 20megaton weapons might be used in order to limit the collateral destruction. After such an attack, one must assume a counterattack, but one may still try to use counter-counterthreats of further escalation into countervalue war to limit the defender's response.
Here, no degradation of the counterforce attack is accepted to spare civilians, but there is no deliberate attempt to enlarge such collateral damage as a "bonus."
Civilian Central Wars (violation of The "no-city" Threshold)
The example of strategic city bombing in World War II is so firmly held in many people's minds as "proper" action that they cannot visualize a large strategic war in which cities are not priority objectives. Yet thermonuclear wars are likely to be short, lasting from a few hours to, at most, a couple of months. In such a war, it is unlikely that cities would in themselves be of any great military consequence: factories would not have time to turn out weapons; millions of men would not be drafted and trained; there probably would not even be elections in which the fears or suffering of the civilian population could generate direct pressures to change established national policies. Thus, cities are no longer urgent military targets; they may be destroyed in a strategic war, but there is no military reason to do so, or to do so quickly. Populations, of course, may be evacuated, but buildings cannot be, and it is unlikely that one side or the other would feel so strongly motivated to destroy civilians early in a war that they would attack to pre-empt such an evacuation.
None of the above is necessarily clearly understood by the governments and war planners of either side. If one side or the other decided to go to war, it might, simply because of this lack of thought, attack cities. Of course, the United States has more or less formally enunciated a strategy of "no cities except in reprisal," but this strategy is neither widely understood nor very firmly held even here. And it remains true that if intrawar deterrence were to break down, or "bargaining" seemed to require it, cities might get hit anyway.
- Slow-Motion Countercity war
- Countervalue Salvo
- Augmented Disarming Attack
- Civilian Devastation Attack
- Controlled General War
- Spasm/Insensate War
A war of resolve (see Rung 33) carried to an ultimate form—"city trading."
It is, of course, always possible in fighting a slow-motion counterforce, slow-motion countervalue, or other kind of war, that one side will fire a large number of missiles at civilian targets, in either inadvertent or deliberate eruption.
This would be a counterforce attack deliberately modified to obtain as a "bonus" as much collateral countervalue damage as could be achieved without diverting significant resources from the military targets.
An effort to destroy or gravely damage the enemy's society, distinguished from spasm war only by its element of calculation and the fact that there may be some withholding or control.
It is possible to have many kinds of "all-out" but controlled, as well as "allout" uncontrolled, wars. (The term "all-out" is enclosed in quotation marks to emphasize again that this is not necessarily a spasm war in which each side strikes indiscriminately against the other's cities and military bases; "all-out" refers to a level of effort, not to whether there is or is not discrimination in targeting, or negotiation.) In a "rational," "all-out," but controlled war, military action would be accompanied by threats and promises, and military operations themselves would be restricted to those which contributed to the achievement of victory (an acceptable or desirable peace treaty), to the limiting of the damage the enemy could do, to the improvement of the nation's postwar prospects (perhaps by worsening the enemy's prospects), or to the gaining of a measured amount of revenge or punishment.
The figurative word "spasm" is chosen because it describes the usual image of central war in which there is only a "go-ahead" order; all the buttons are pressed, and the decision-makers and their staffs go home—if they still have homes; they have done their job. A spasm war may occur, of course, but to the extent that there is any art of war possible in the thermonuclear age, the attempt must be made to prevent it, to try to get the losing side to cease fire before he has used up his weapons. In a "moment of truth," and particularly if there has been a preliminary crisis that has educated the leaders, all decisionmakers are likely to understand at least to some degree that there need be no compulsion to wreak useless and contraproductive destruction just because one has weapons that can be used.
There may be situations in which striking a center of gravity might deliver a fatal blow; but the enemy might still be able to retaliate with a lethal or unacceptably damaging response, much like a spider whose legs continue to strike after it is dead. This phenomenon is referred to as “insensate war" and it is still a possibility in today’s globalized world.