Kahn's Escalation Ladder

Subcrisis Maneuvering

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.

1. Ostensible Crisis

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.

2. Political, Economic and Diplomatic Gestures

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"

3. Solemn and Formal Declarations

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.

4. Hardening of Positions -- Confrontation of Wills

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.

5. Show of Force

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."

6. Significant Mobilization

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.

7. "Legal" Harassment -- Retortions

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.

8. Harassing Acts of Violence

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.

9. Dramatic Military Confrontations

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.

Intense Crises

Nuclear War is Unthinkable Threshold

10. Provocative Breaking off of Diplomatic Relations
11. Super-Ready Status
12. Large Conventional War (or Actions)
13. Large Compound Escalator
14. Declaration of Limited Conventional War
15. Barely Nuclear War

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.

16. Nuclear "Ultimatums"

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.

17. Limited Evaluations (20%)

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.

18. Spectacular Show or Demonstration of Force

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.

19. "Justifiable" Counterforce Attack

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.

20. "Peaceful" World-Wide Embargo or Blockade

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.

21. Local Nuclear War -- Exemplary

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.

22. Declaration of Limited Nuclear War

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.

23. Local Nuclear War -- Military

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.

24. Unusual, Provocative and Significant Countermeasures

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.

25. Evacuation (70%)

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.

26. Demonstration Attack on Zone of Interior

A "harmless" attack (perhaps on an isolated mountain top or empty desert) which does dramatic and unmistakable physical damage, if only to the topography.

27. Exemplary Attack on Military

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.

28. Exemplary Attacks Against Property

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.

29. Exemplary Attacks on Population

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.

30. Complete Evacuation (95%)

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.

31. Reciprocal Reprisals

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.

32. Formal Declaration of "General" War

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.

33. Slow-Motion Counter-"Property" War

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).

34. Slow-Motion Counterforce War

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.

35. Constrained Force-Reduction Salvo

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.

36. Constrained Disarming Attack

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.

37. Counterforce-with-Avoidance Attack

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.

38. Unmodified Counterforce Attack

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.

39. Slow-Motion Countercity war

A war of resolve (see Rung 33) carried to an ultimate form—"city trading."

40. Countervalue Salvo

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.

41. Augmented Disarming Attack

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.

42. Civilian Devastation Attack

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.

43. Controlled General War

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.

44. Spasm/Insensate War

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.