No one seems to doubt that federal troops are available to defend California. I have, however, heard Frenchmen doubt whether American troops can be counted on to defend France, or American missiles to blast Russia in case France is attacked.
[…]
It is a tradition in military planning to attend to an enemy’s capabilities, not his intentions. But deterrence is about intentions—not just estimating enemy intentions but influencing them. The hardest part is communicating our own intentions.
[…]
Nations have been known to bluff; they have also been known to make threats sincerely and change their minds when the chips were down.
[…]
When Churchill said that the British would fight on the beaches nobody supposed that he had sat up all night running once more through the calculations to make sure that was the right policy. Declaring war against Germany for the attack on Poland, though, was a different kind of decision, not a simple reflex but a matter of “policy.” Some threats are inherently persuasive, some have to be made persuasive, and some are bound to look like bluffs.
[…]
As a tentative approximation—a very tentative one—the difference between the national homeland and everything “abroad” is the difference between threats that are inherently credible, even if unspoken, and the threats that have to be made credible.
[…]
It is a paradox of deterrence that in threatening to hurt somebody if he misbehaves, it need not make a critical difference how much it would hurt you too—if you can make him believe the threat. People walk against traffic lights on busy streets, deterring trucks by walking in front of them.
[…]
Another paradox of deterrence is that it does not always help to be, or to be believed to be, fully rational, cool-headed, and in control of oneself or of one’s country. One of Joseph Conrad’s books, The Secret Agent, concerns a group of anarchists in London who were trying to destroy bourgeois society. One of their techniques was bomb explosions; Greenwich Observatory was the objective in this book. They got their nitroglycerin from a stunted little chemist. The authorities knew where they got their stuff and who made it for them. But this little purveyor of nitroglycerin walked safely past the London police. A young man who was tied in with the job at Greenwich asked him why the police did not capture him. His answer was that they would not shoot him from a distance—that would be a denial of bourgeois morality, and serve the anarchists’ cause—and they dared not capture him physically because he always kept some “stuff” on his person. He kept a hand in his pocket, he said, holding a ball at the end of a tube that reached a container of nitroglycerin in his jacket pocket. All he had to do was to press that little ball and anybody within his immediate neighborhood would be blown to bits with him. His young companion wondered why the police would believe anything so preposterous as that the chemist would actually blow himself up. The little man’s explanation was calm. “In the last instance it is character alone that makes for one’s safety . . . I have the means to make myself deadly, but that by itself, you understand, is absolutely nothing in the way of protection. What is effective is the belief those people have in my will to use the means. That’s their impression. It is absolute. Therefore I am deadly.”
[…]
I have been told that in mental institutions there are inmates who are either very crazy or very wise, or both, who make clear to the attendants that they may slit their own veins or light their clothes on fire if they don’t have their way. I understand that they sometimes have their way.
Recall the trouble we had persuading Mossadegh in the early 1950s that he might do his country irreparable damage if he did not become more reasonable with respect to his country and the Anglo-Iranian Oil Company. Threats did not get through to him very well. He wore pajamas, and, according to reports, he wept. And when British or American diplomats tried to explain what would happen to his country if he continued to be obstinate, and why the West would not bail him out of his difficulties, it was apparently uncertain whether he even comprehended what was being said to him. It must have been a little like trying to persuade a new puppy that you will beat him to death if he wets on the floor. If he cannot hear you, or cannot understand you, or cannot control himself, the threat cannot work and you very likely will not even make it.
[…]
There have been serious suggestions that nuclear weapons should be put directly at the disposal of German troops, on the grounds that the Germans would be less reluctant to use them—and that Soviet leaders know they would be less reluctant—than their American colleagues in the early stages of war or ambiguous aggression. And in part, the motive behind the proposals that authority to use nuclear weapons be delegated in peacetime to theater commanders or even lower levels of command, as in the presidential campaign of 1964, is to substitute military boldness for civilian hesitancy in a crisis or at least to make it look that way to the enemy. Sending a high-ranking military officer to Berlin, Quemoy, or Saigon in a crisis carries a suggestion that authority has been delegated to someone beyond the reach of political inhibition and bureaucratic delays, or even of presidential responsibility, someone whose personal reactions will be in a bold military tradition. The intense dissatisfaction of many senators with President Kennedy’s restraint over Cuba in early 1962, and with the way matters were left at the close of the crisis in that November, though in many ways an embarrassment to the President, may nevertheless have helped to convey to the Cubans and to the Soviets that, however peaceable the President might want to be, there were political limits to his patience.
[…]
“If you send in tanks, they will burn and make no mistake about it. If you want war, you can have it, but remember it will be your war. Our rockets will fly automatically.” At this point, according to Harriman, Khrushchev’s colleagues around the table chorused the word “automatically.”
[…]
General Pierre Gallois, an outstanding French critic of American military policy, has credited Khrushchev with a “shrewd understanding of the politics of deterrence,” evidenced by this “irrational outburst” in the presence of Secretary Harriman.
[…]
We ought to get something a little less idiosyncratic for 50 billion dollars a year of defense expenditure. A government that is obliged to appear responsible in its foreign policy can hardly cultivate forever the appearance of impetuosity on the most important decisions in its care.
[…]
President Kennedy chose a most impressive occasion for his declaration on “automaticity.” It was his address of October 22, 1962, launching the Cuban crisis. In an unusually deliberate and solemn statement he said, “Third: it shall be the policy of this nation to regard any nuclear missile launched from Cuba against any nation in the Western hemisphere as an attack by the Soviet Union on the United States, requiring a full retaliatory response upon the Soviet Union.” Coming less than six months after Secretary McNamara’s official elucidation of the strategy of controlled and flexible response, the reaction implied in the President’s statement would have been not only irrational but probably—depending on just what “full retaliatory response” meant to the President or to the Russians—inconsistent with one of the foundations of the President’s own military policy, a foundation that was laid as early as his first defense budget message of 1961, which stressed the importance of proportioning the response to the provocation, even in war itself.
[…]
As a matter of fact it is most unlikely—actually it is inconceivable—that in preparing his address the President sent word to senior military and civilian officials that this particular paragraph of his speech was not to be construed as policy.
[…]
Often we must maneuver into a position where we no longer have much choice left. This is the old business of burning bridges. If you are faced with an enemy who thinks you would turn and run if he kept advancing, and if the bridge is there to run across, he may keep advancing. He may advance to the point where, if you do not run, a clash is automatic. Calculating what is in your long-run interest, you may turn and cross the bridge. At least, he may expect you to. But if you burn the bridge so that you cannot retreat, and in sheer desperation there is nothing you can do but defend yourself, he has a new calculation to make. He cannot count on what you would prefer to do if he were advancing irresistibly; he must decide instead what he ought to do if you were incapable of anything but resisting him.
This is the position that Chiang Kai-shek got himself into, and us with him, when he moved a large portion of his best troops to Quemoy. Evacuation under fire would be exceedingly difficult; if attacked, his troops had no choice but to fight, and we probably had no choice but to assist them. It was undoubtedly a shrewd move from Chiang’s point of view—coupling himself, and the United States with him, to Quemoy—and in fact if we had wanted to make clear to the Chinese Communists that Quemoy had to be defended if they attacked it, it would even have been a shrewd move also from our point of view.
This idea of burning bridges—of maneuvering into a position where one clearly cannot yield—conflicts somewhat, at least semantically, with the notion that what we want in our foreign policy is “the initiative.” Initiative is good if it means imaginativeness, boldness, new ideas. But the term somewhat disguises the fact that deterrence, particularly deterrence of anything less than mortal assault on the United States, often depends on getting into a position where the initiative is up to the enemy and it is he who has to make the awful decision to proceed to a clash.
In recent years it has become something of a principle in the Department of Defense that the country should have abundant “options” in its choice of response to enemy moves. The principle is a good one, but so is a contrary principle—that certain options are an embarrassment. The United States government goes to great lengths to reassure allies and to warn Russians that it has eschewed certain options altogether, or to demonstrate that it could not afford them or has placed them out of reach. The commitment process on which all American overseas deterrence depends—and on which all confidence within the alliance depends—is a process of surrendering and destroying options that we might have been expected to find too attractive in an emergency. We not only give them up in exchange for commitments to us by our allies; we give them up on our own account to make our intentions clear to potential enemies. In fact, we do it not just to display our intentions but to adopt those intentions. If deterrence fails it is usually because someone thought he saw an “option” that the American government had failed to dispose of, a loophole that it hadn’t closed against itself.
At law there is a doctrine of the “last clear chance.” It recognizes that, in the events leading up to an accident, there was some point prior to which either party could avert collision, some point after which neither could, and very likely a period between when one party could still control events but the other was helpless to turn aside or stop. The one that had the “last clear chance” to avert collision is held responsible. In strategy when both parties abhor collision the advantage goes often to the one who arranges the status quo in his favor and leaves to the other the “last clear chance” to stop or turn aside. Xenophon understood the principle when, threatened by an attack he had not sought, he placed his Greeks with their backs against an impassable ravine. “I should like the enemy to think it is easy-going in every direction for him to retreat.” And when he had to charge a hill occupied by aliens, he “did not attack from every direction but left the enemy a way of escape, if he wanted to run away.” The “last chance” to clear out was left to the enemy when Xenophon had to take the initiative, but denied to himself when he wanted to deter attack, leaving his enemy the choice to attack or retire.
[…]
It was typically agreed, especially at summit meetings, that nobody wanted a war. Khrushchev’s complacent remark, based on Berlin’s being on his side of the border, was that Berlin was not worth a war. As the story goes, he was reminded that Berlin was not worth a war to him either. “No,” he replied, “but you are the ones that have to cross a frontier.” The implication, I take it, was that neither of us wanted to cross that threshold just for Berlin, and if Berlin’s location makes us the ones who have to cross the border, we are the ones who let it go though both of us are similarly fearful of war.
[…]
To have told the Soviets in the late 1940s that, if they attacked, we were obliged to defend Europe might not have been wholly convincing. When the Administration asked Congress for authority to station Army divisions in Europe in peacetime, the argument was explicitly made that these troops were there not to defend against a superior Soviet army but to leave the Soviet Union in no doubt that the United States would be automatically involved in the event of any attack on Europe. The implicit argument was not that since we obviously would defend Europe we should demonstrate the fact by putting troops there. The reasoning was probably that, whether we wished to be or not, we could not fail to be involved if we had more troops being run over by the Soviet Army than we could afford to see defeated. Notions like “trip wire” or “plate glass window,” though oversimplified, were attempts to express this role. And while “trip wire” is a belittling term to describe an army, the role is not a demeaning one. The garrison in Berlin is as fine a collection of soldiers as has ever been assembled, but excruciatingly small. What can 7,000 American troops do, or 12,000 Allied troops? Bluntly, they can die. They can die heroically, dramatically, and in a manner that guarantees that the action cannot stop there. They represent the pride, the honor, and the reputation of the United States government and its armed forces; and they can apparently hold the entire Red Army at bay. Precisely because there is no graceful way out if we wished our troops to yield ground, and because West Berlin is too small an area in which to ignore small encroachments, West Berlin and its military forces constitute one of the most impregnable military outposts of modern times. The Soviets have not dared to cross that frontier.
Berlin illustrates two common characteristics of these commitments. The first is that if the commitment is ill defined and ambiguous—if we leave ourselves loopholes through which to exit—our opponent will expect us to be under strong temptation to make a graceful exit (or even a somewhat graceless one) and he may be right. The western sector of Berlin is a tightly defined piece of earth, physically occupied by Western troops: our commitment is credible because it is inescapable.
[…]
The second thing that Berlin illustrates is that, however precisely defined is the issue about which we are committed, it is often uncertain just what we are committed to do. The commitment is open-ended. Our military reaction to an assault on West Berlin is really not specified. We are apparently committed to holding the western sector of the city if we can; if we are pushed back, we are presumably committed to repelling the intruders and restoring the original boundary. If we lose the city, we are perhaps committed to reconquering it. But somewhere in this sequence of events things get out of hand, and the matter ceases to be purely one of restoring the status quo in Berlin. Military instabilities may arise that make the earlier status quo meaningless. A costly reestablishment of the status quo might call for some sort of reprisal, obliging some counteraction in return. Just what would happen is a matter of prediction, or guess. What we seem to be committed to is action of some sort commensurate with the provocation. Military resistance tends to develop a momentum of its own. It is dynamic and uncertain. What we threaten in Berlin is to initiate a process that may quickly get out of hand.
The maneuver in Lebanon in 1958—the landing of troops in a developing crisis—though not one of the neatest political–military operations of recent times, represented a similar strategy. Whatever the military potential of the ten or twelve thousand troops that we landed in Lebanon—and it would depend on who might have engaged them, where, over what issue—they had the advantage that they got on the ground before any Soviet adventure or movement was under way. The landing might be described as a “preemptive maneuver.” From then on, any significant Soviet intervention in the affairs of Lebanon, Jordan, or even Iraq, would have substantially raised the likelihood that American and Soviet forces, or American and Soviet-supported forces, would be directly engaged.
In effect, it was Khrushchev’s turn to cross a border. Iraq or Jordan might not have been worth a war to either of us but by getting troops on the soil—or, as we used to say, the American flag—we probably made it clear to the Kremlin that we could not gracefully retreat under duress. It is harder to retreat than not to land in the first place; the landing helped to put the next step up to the Russians.
In addition to getting yourself where you cannot retreat, there is a more common way of making a threat. That is to incur a political involvement, to get a nation’s honor, obligation, and diplomatic reputation committed to a response. The Formosa resolution of 1955, along with the military assistance agreement then signed by the United States and the National Government of the Republic of China, should probably be interpreted that way. It was not mainly a technique for reassuring Chiang Kai-shek that we would defend him, and it was not mainly a quid pro quo for something he did for us. It was chiefly important as a move to impress a third party. The primary audience for the congressional action was inside the Soviet bloc. The resolution, together with the treaty, was a ceremony to leave the Chinese and the Russians under no doubt that we could not back down from the defense of Formosa without intolerable loss of prestige, reputation, and leadership. We were not merely communicating an intention or obligation we already had, but actually enhancing the obligation in the process. The congressional message was not, “Since we are obliged to defend Formosa, we may as well show it.” Rather: “In case we were not sufficiently committed to impress you, now we are. We hereby oblige ourselves. Behold us in the public ritual of getting ourselves genuinely committed.”
That kind of commitment is not to be had cheaply. If Congress passed such a resolution for every small piece of the world that it would like the Soviets to leave alone, it would cheapen the currency. A nation has limited resources, so to speak, in the things that it can get exceptionally concerned about. Political involvement within a country is not something that can be had for the price of a casual vote or a signature on a piece of paper.
[…]
One of the lessons of November 1962 may be that, in the face of anything quite as adventuresome as an effort to take over a country the size of India, we may be virtually as committed as if we had a mutual assistance treaty. We cannot afford to let the Soviets or Communist Chinese learn by experience that they can grab large chunks of the earth and its population without a genuine risk of violent Western reaction.
Our commitment to Quemoy, which gave us concern in 1955 and especially in 1958, had not been deliberately conceived; and it appeared at the time to be a genuine embarrassment. For reasons that had nothing to do with American policy, Quemoy had been successfully defended by the Nationalists when Chiang Kai-shek evacuated the mainland, and it remained in Nationalist hands. By the time the United States assumed the Commitment to Formosa, the island of Quemoy stood as a ragged edge about which our intentions were ambiguous. Secretary Dulles in 1958 expressed the official view that we could not afford to vacate Quemoy under duress. The implication seemed to be that we had no genuine desire to take risks for Quemoy and might have preferred it if Quemoy had fallen to the Communists in 1949; but our relations with Communist China were at stake once Quemoy became an issue. So we had a commitment that we might have preferred not to have. And in case that commitment did not appear firm enough, Chiang Kai-shek increased it for us by moving enough of his best troops to that island, under conditions in which evacuation under attack would have been difficult, to make clear that he had to defend it or suffer military disaster, leaving it up to the United States to bail him out.
[…]
We cannot afford to let the Soviets overrun West Germany or Greece, irrespective of our treaty commitments to Germany or to the rest of Western Europe.
[…]
It is interesting that any “commitment” we had to keep India from being conquered or destroyed by Communist China was not mainly a commitment to the Indians or their government. We wanted to restrain Communist China generally; we wanted to give confidence to other governments in Asia; and we wanted to preserve confidence in our deterrent role all the way around the world to Europe. Military support to India would be a way of keeping an implicit pledge but the pledge was a general one, not a debt owed to the Indians. When a disciplinarian—police or other—intervenes to resist or punish someone’s forbidden intrusion or assault, any benefit to the victim of the intrusion or assault may be incidental. He could even prefer not to be fought over; but if the issue is maintenance of discipline, he may not have much say in the matter.
[…]
There has been a lot of discussion about whether we were or were not “committed” to the defense of South Korea. From what I have seen of the way the decision to intervene was taken, first by participation of American military assistance forces, then by bombing, then with reinforcements, and finally with a major war effort, one could not confidently have guessed in May 1950 what the United States would do.
[…]
And we seem to have misread the Chinese warnings during our advance toward the Yalu River. Allen Whiting has documented a serious Chinese Communist attempt to warn the Americans that they would engage us militarily rather than let us occupy all of North Korea.
[…]
The reason we got committed to the defense of Berlin, and stayed committed, is that if we let the Soviets scare us out of Berlin we would lose face with the Soviets themselves. The reputation that most matters to us is our reputation with the Soviet (and Communist Chinese) leaders. It would be bad enough to have Europeans, Latin Americans, or Asians think that we are immoral or cowardly. It would be far worse to lose our reputation with the Soviets. When we talk about the loss of face that would occur if we backed out of Formosa under duress, or out of Berlin, the loss of face that matters most is the loss of Soviet belief that we will do, elsewhere and subsequently, what we insist we will do here and now. Our deterrence rests on Soviet expectations.
[…]
There is an interesting geographical difference in the Soviet and American homelands; it is hard to imagine a war so located that it could spill over by hot pursuit, by interdiction bombing, by inadvertent border violation, by local reprisal bombing, or even by deliberate but limited ground encroachment into American territory. Our oceans may not protect us from big wars but they protect us from little ones. A local war could not impinge on California, involving it peripherally or incidentally through geographical continuity, the way the Korean War could impinge on Manchuria and Siberia, or the way Soviet territory could be impinged on by war in Iran, Yugoslavia, or Central Europe. One can argue about how far back toward Moscow an “interdiction campaign” of bombing might have to reach, or might safely reach, in case of a limited war in Central Europe; and there is no geographical feature—and few economic features—to present a sudden discontinuity at the Soviet border. A comparable question hardly arises for American participation in the same war; there is one discontinuity leading to submarine warfare on the high seas, and another, a great one, in going inland to the railroad tracks that carry the freight to the Baltimore docks. The vehicles or vessels that would have to carry out the intrusion would furthermore be different in character from those involved in the “theater war.”
[…]
One of the arguments that has been made, and taken seriously, against having all of our strategic weapons at sea or in outer space or even emplaced abroad, is that the enemy might be able to attack them without fearing the kind of response that would be triggered by an attack on our homeland. If all missiles were on ships at sea, the argument runs, an attack on a ship would not be quite the same as an attack on California or Massachusetts; and an enemy might consider doing it in circumstances when he would not consider attacking weapons located on our soil. (An extreme form of the argument, not put forward quite so seriously, was that we ought to locate our weapons in the middle of population centers, so that the enemy could never attack them without arousing the massive response that he could take for granted if he struck our cities.)
There is something to the argument. If in an Asian war we flew bombers from aircraft carriers or from bases in an allied country, and an enemy attacked our ships at sea or our overseas bases, we would almost certainly not consider it the same as if we had flown the bombers from bases in Hawaii or California and he had attacked the bases in those states. If the Soviets had put nuclear weapons in orbit and we shot at them with rockets the results might be serious, but not the same as if the Soviets had put missiles on home territory and we shot at those missiles on their home grounds.
[…]
(One of the arguments made against the use of surface ships in a European Multilateral Force armed with long-range missiles was that they could be picked off by an enemy, possibly during a limited war in which the Multilateral Force was not engaged, possibly without the use of nuclear weapons by an enemy, in a way that would not quite provoke reprisal, and thus would be vulnerable in a way that homeland-based missiles would not be.)
The argument can go either way. This can be a reason for deliberately putting weapons outside our boundary, so that their military involvement would not tempt an attack on our homeland, or for keeping them within our boundaries so that an attack on them would appear the more risky.
[…]
And I have heard it argued that the Soviets, if they fear for the deterrent security of their retaliatory forces in a purely “military” war that the Americans might initiate, may actually prefer a close proximity of their missiles to their cities to make the prospect of a “clean” strategic war, one without massive attacks on cities, less promising—to demonstrate that there would remain little to lose, after an attack on their weapons, and little motive to confine their response to military targets. The policy would be a dangerous one if there were much likelihood that war would occur, but its logic has merit.
[…]
If we always treat China as though it is a Soviet California, we tend to make it so. If we imply to the Soviets that we consider Communist China or Czechoslovakia the virtual equivalent of Siberia, then in the event of any military action in or against those areas we have informed the Soviets that we are going to interpret their response as though we had landed troops in Vladivostok or Archangel or launched them across the Soviet-Polish border. We thus oblige them to react in China, or in North Vietnam or wherever it may be, and in effect give them precisely the commitment that is worth so much to them in deterring the West. If we make it clear that we believe they are obliged to react to an intrusion in Hungary as though we were in the streets of Moscow, then they are obliged.
]…]
Certain things like honor and outrage are not meant to be matters of degree. One can say that his homeland is inviolate only if he knows exactly what he means by “homeland” and it is not cluttered up with full-fledged states, protectorates, territories, and gradations of citizenship that make some places more “homeland” than others. Like virginity, the homeland wants an absolute definition.
[…]
We came at last to treat the Sino-Soviet split as a real one; but it would have been wiser not to have acknowledged their fusion in the first place. In our efforts to dramatize and magnify the Soviet threat, we sometimes present the Soviet Union with a deterrent asset of a kind that we find hard to create for ourselves.
[…]
Sometimes a country wants to get out of a commitment—to decouple itself. It is not easy. We may have regretted our commitment to Quemoy in 1958, but there was no graceful way to undo it at that time. The Berlin wall was a genuine embarrassment. We apparently had not enough of a commitment to feel obliged to use violence against the Berlin wall. We had undeniably some commitment; there was some expectation that we might take action and some belief that we ought to. We did not, and it cost us something. If nobody had ever expected us to do anything about the wall—if we had never appeared to have any obligation to prevent things like the wall, and if we had never made any claims about East Berlin that seemed inconsistent with the wall—the wall would have embarrassed us less.
[…]
The Soviets had a similar problem over Cuba. Less than six weeks before the President’s missile crisis address of October 22, 1962, the Soviet government had issued a formal statement about Cuba. “We have said and do repeat that if war is unleashed, if the aggressor makes an attack on one state or another and this state asks for assistance, the Soviet Union has the possibility from its own territory to render assistance to any peace-loving state and not only to Cuba. And let no one doubt that the Soviet Union will render such assistance.” And further, “The Soviet government would like to draw attention to the fact that one cannot now attack Cuba and expect that the aggressor will be free from punishment for this attack. If this attack is made, this will be the beginning of the unleashing of war.” It was a long, argumentative statement, however, and acknowledged that “only a madman can think now that a war started by him will be a calamity only for the people against which it is unleashed.” And the most threatening language was not singled out for solemn treatment but went along as part of the argument. So there was at least a degree of ambiguity.
President Kennedy’s television broadcast of October 22 was directly aimed at the Soviet Union. It was so directly aimed that one can infer only a conscious decision to make this not a Caribbean affair but an East–West affair. It concerned Soviet missiles and Soviet duplicity, a Soviet challenge; and the President even went out of his way to express concern for the Cubans, his desire that they not be hurt, and his regret for the “foreign domination” that was responsible for their predicament. The President did not say that we had a problem with Cuba and hoped the Soviets would keep out of it; he said we had an altercation with the Soviet Union and hoped Cubans would not be hurt.
[…]
But just as one cannot incur a genuine commitment by purely verbal means, one cannot get out of it with cheap words either. Secretary Dulles in 1958 could not have said, “Quemoy? Who cares about Quemoy? It’s not worth fighting over, and our defense perimeter will be neater without it.” The United States never did talk its way cleanly out of the Berlin wall business. Even if the letter of our obligations was never violated, there are bound to be some who think the spirit demanded more. We had little obligation to intervene in Hungary in 1956, and the Suez crisis confused and screened it. Nevertheless, there was a possibility that the West might do something and it did not. Maybe this was a convenience, clarifying an implicit understanding between East and West. But the cost was not zero.
If commitments could be undone by declaration they would be worthless in the first place. The whole purpose of verbal or ritualistic commitments, of political and diplomatic commitments, of efforts to attach honor and reputation to a commitment, is to make the commitment manifestly hard to get out of on short notice. Even the commitments not deliberately incurred, and the commitments that embarrass one in unforeseen circumstances, cannot be undone cheaply. The cost is the discrediting of other commitments that one would still like to be credited.
[…]
The Chinese Communists seemed not to be trying, from 1958 on, to make it easy for the United States to decouple itself from Quemoy. They maintained, and occasionally intensified, enough military pressure on the island to make graceful withdrawal difficult, to make withdrawal look like retreat under duress. It is hard to escape the judgment that they enjoyed American discomfort over Quemoy, their own ability to stir things up at will but to keep crises under their control, and their opportunity to aggravate American differences with Chiang Kai-shek.
“Salami tactics,” we can be sure, were invented by a child; whoever first expounded the adult version had already understood the principle when he was small. Tell a child not to go in the water and he’ll sit on the bank and submerge his bare feet; he is not yet “in” the water. Acquiesce, and he’ll stand up; no more of him is in the water than before. Think it over, and he’ll start wading, not going any deeper; take a moment to decide whether this is different and he’ll go a little deeper, arguing that since he goes back and forth it all averages out. Pretty soon we are calling to him not to swim out of sight, wondering whatever happened to all our discipline.
[…]
No matter how inviolate our commitment to some border, we are unlikely to start a war the first time a few drunken soldiers from the other side wander across the line and “invade” our territory. And there is always the possibility that some East German functionary on the Autobahn really did not get the word, or his vehicle really did break down in our lane of traffic. There is some threshold below which the commitment is just not operative, and even that threshold itself is usually unclear.
From this arises the low-level incident or probe, and tactics of erosion. One tests the seriousness of a commitment by probing it in a noncommittal way, pretending the trespass was inadvertent or unauthorized if one meets resistance, both to forestall the reaction and to avoid backing down. One stops a convoy or overflies a border, pretending the incident was accidental or unauthorized; but if there is no challenge, one continues or enlarges the operation, setting a precedent, establishing rights of thoroughfare or squatters’ rights, pushing the commitment back or raising the threshold. The use of “volunteers” by Soviet countries to intervene in trouble spots was usually an effort to sneak under the fence rather than climb over it, not quite invoking the commitment, but simultaneously making the commitment appear porous and infirm. And if there is no sharp qualitative division between a minor transgression and a major affront, but a continuous gradation of activity, one can begin his intrusion on a scale too small to provoke a reaction, and increase it by imperceptible degrees, never quite presenting a sudden, dramatic challenge that would invoke the committed response. Small violations of a truce agreement, for example, become larger and larger, and the day never comes when the camel’s back breaks under a single straw.
[…]
If the committed country has a reputation for sometimes, unpredictably, reacting where it need not, and not always collaborating to minimize embarrassment, loopholes may be less inviting. If one cannot get a reputation for always honoring commitments in detail, because the details are ambiguous, it may help to get a reputation for being occasionally unreasonable. If one cannot buy clearly identifiable and fully reliable trip-wires, an occasional booby trap placed at random may serve somewhat the same purpose in the long run.
Landlords rarely evict tenants by strong-arm methods. They have learned that steady cumulative pressures work just as well, though more slowly, and avoid provoking a violent response. It is far better to turn off the water and the electricity, and let the tenant suffer the cumulative pressure of unflushed toilets and candles at night and get out voluntarily, than to start manhandling his family and his household goods. Blockade works slowly; it puts the decision up to the other side. To invade Berlin or Cuba is a sudden identifiable action, of an intensity that demands response; but to cut off supplies does little the first day and not much more the second; nobody dies or gets hurt from the initial effects of a blockade. A blockade is comparatively passive; the eventual damage results as much from the obstinacy of the blockaded territory as from the persistence of the blockading power. And there is no well-defined moment before which the blockading power may quail, for fear of causing the ultimate collapse.
President Truman appreciated the value of this tactic in June 1945. French forces under de Gaulle’s leadership had occupied a province in Northern Italy, contrary to Allied plans and American policy. They announced that any effort of their allies to dislodge them would be treated as a hostile act. The French intended to annex the area as a “minor frontier adjustment.” It would have been extraordinarily disruptive of Allied unity, of course, to expel the French by force of arms; arguments got nowhere, so President Truman notified de Gaulle that no more supplies would be issued to the French army until it had withdrawn from the Aosta Valley. The French were absolutely dependent on American supplies and the message brought results. This was “nonhostile” pressure, not quite capable of provoking a militant response, therefore safe to use (and effective).
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Blockade illustrates the typical difference between a threat intended to make an adversary do something and a threat intended to keep him from starting something. The distinction is in the timing and in the initiative, in who has to make the first move, in whose initiative is put to the test. To deter an enemy’s advance it may be enough to burn the escape bridges behind me, or to rig a trip-wire between us that automatically blows us both up when he advances. To compel an enemy’s retreat, though, by some threat of engagement, I have to be committed to move. (This requires setting fire to the grass behind me as I face the enemy, with the wind blowing toward the enemy.) I can block your car by placing mine in the way; my deterrent threat is passive, the decision to collide is up to you. But if you find me in your way and threaten to collide unless I move, you enjoy no such advantage; the decision to collide is still yours, and I still enjoy deterrence. You have to arrange to have to collide unless I move, and that is a degree more complicated. You have to get up so much speed that you cannot stop in time and that only I can avert the collision; this may not be easy. If it takes more time to start a car than to stop one, you may be unable to give me the “last clear chance” to avoid collision by vacating the street.
The threat that compels rather than deters often requires that the punishment be administered until the other acts, rather than if he acts. This is because often the only way to become committed to an action is to initiate it. This means, though, that the action initiated has to be tolerable to the initiator, and tolerable over whatever period of time is required for the pressure to work on the other side. For deterrence, the trip-wire can threaten to blow things up out of all proportion to what is being protected, because if the threat works the thing never goes off. But to hold a large bomb and threaten to throw it unless somebody moves cannot work so well; the threat is not believable until the bomb is actually thrown and by then the damage is done.
There is, then, a difference between deterrence and what we might, for want of a better word, call compellence. The dictionary’s definition of “deter” corresponds to contemporary usage: to turn aside or discourage through fear; hence, to prevent from action by fear of consequences. A difficulty with our being an unaggressive nation, one whose announced aim has usually been to contain rather than to roll back, is that we have not settled on any conventional terminology for the more active kind of threat. We have come to use “defense” as a euphemism for “military,” and have a Defense Department, a defense budget, a defense program, and a defense establishment; if we need the other word, though, the English language provides it easily. It is “offense.” We have no such obvious counterpart to “deterrence.” “Coercion” covers the meaning but unfortunately includes “deterrent” as well as “compellent” intentions. “Intimidation” is insufficiently focused on the particular behavior desired. “Compulsion” is all right but its adjective is “compulsive,” and that has come to carry quite a different meaning. “Compellence” is the best I can do.
Deterrence and compellence differ in a number of respects, most of them corresponding to something like the difference between statics and dynamics. Deterrence involves setting the stage—by announcement, by rigging the trip-wire, by incurring the obligation—and waiting. The overt act is up to the opponent. The stage-setting can often be nonintrusive, nonhostile, nonprovocative. The act that is intrusive, hostile, or provocative is usually the one to be deterred; the deterrent threat only changes the consequences if the act in question—the one to be deterred—is then taken. Compellence, in contrast, usually involves initiating an action (or an irrevocable commitment to action) that can cease, or become harmless, only if the opponent responds. The overt act, the first step, is up to the side that makes the compellent threat. To deter, one digs in, or lays a minefield, and waits—in the interest of inaction. To compel, one gets up enough momentum (figuratively, but sometimes literally) to make the other act to avoid collision.
Deterrence tends to be indefinite in its timing. “If you cross the line we shoot in self-defense, or the mines explode.” When? Whenever you cross the line—preferably never, but the timing is up to you. If you cross it, then is when the threat is fulfilled, either automatically, if we’ve rigged it so, or by obligation that immediately becomes due. But we can wait—preferably forever; that’s our purpose.
Compellence has to be definite: We move, and you must get out of the way. By when? There has to be a deadline, otherwise tomorrow never comes. If the action carries no deadline it is only a posture, or a ceremony with no consequences. If the compellent advance is like Zeno’s tortoise that takes infinitely long to reach the border by traversing, with infinite patience, the infinitely small remaining distances that separate him from collision, it creates no inducement to vacate the border. Compellence, to be effective, can’t wait forever. Still, it has to wait a little; collision can’t be instantaneous. The compellent threat has to be put in motion to be credible, and then the victim must yield. Too little time, and compliance becomes impossible; too much time, and compliance becomes unnecessary. Thus compellence involves timing in a way that deterrence typically does not.
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Actually, any coercive threat requires corresponding assurances; the object of a threat is to give somebody a choice. To say, “One more step and I shoot,” can be a deterrent threat only if accompanied by the implicit assurance, “And if you stop I won’t.” Giving notice of unconditional intent to shoot gives him no choice (unless by behaving as we wish him to behave the opponent puts himself out of range, in which case the effective threat is, “Come closer and my fire will kill you, stay back and it won’t”).
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(Ordinary blackmailers, not just nuclear, find the “assurances” troublesome when their threats are compellent.)
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Because in the West we deal mainly in deterrence, not compellence, and deterrent threats tend to convey their assurances implicitly, we often forget that both sides of the choice, the threatened penalty and the proffered avoidance or reward, need to be credible.
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Blockade, harassment, and “salami tactics” can be interpreted as ways of evading the dangers and difficulties of compellence. Blockade in a cold war sets up a tactical “status quo” that is damaging in the long run but momentarily safe for both sides unless the victim tries to run the blockade. President Kennedy’s overt act of sending the fleet to sea, in “quarantine” of Cuba in October 1962, had some of the quality of deterrent “stage setting”; the Soviet government then had about forty-eight hours to instruct its steamers whether or not to seek collision. Low-level intrusion, as discussed earlier, can be a way of letting the opponent turn his head and yield a little, or it can be a way of starting a compellent action in low gear, without the conviction that goes with greater momentum but also without the greater risk. Instead of speeding out of control toward our car that blocks his way, risking our inability to see him and get our engines started in time to clear his path, he approaches slowly and nudges fenders, crushing a few lights and cracking some paint. If we yield he can keep it up, if not he can cut his losses. And if he makes it look accidental, or can blame it on an impetuous chauffeur, he may not even lose countenance in the unsuccessful try.
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If the object, and the only hope, is to resist successfully, so that the enemy cannot succeed even if he tries, we can call it pure defense. If the object is to induce him not to proceed, by making his encroachment painful or costly, we can call it a “coercive” or “deterrent” defense.
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Defensive action may even be undertaken with no serious hope of repelling or deterring enemy action but with a view to making a “successful” conquest costly enough to deter repetition by the same opponent or anyone else. This is of course the rationale for reprisals after the fact; they cannot undo the deed but can make the books show a net loss and reduce the incentive next time. Defense can sometimes get the same point across, as the Swiss demonstrated in the fifteenth century by the manner in which they lost battles as well as by the way they sometimes won them. “The [Swiss] Confederates were able to reckon their reputation for obstinate and invincible courage as one of the chief causes which gave them political importance. . . . It was no light matter to engage with an enemy who would not retire before any superiority in numbers, who was always ready for a fight, who would neither give nor take quarter.”
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A blockade was thrown around the island, a blockade that by itself could not make the missiles go away. The blockade did, however, threaten a minor military confrontation with major diplomatic stakes—an encounter between American naval vessels and Soviet merchant ships bound for Cuba. Once in place, the Navy was in a position to wait; it was up to the Russians to decide whether to continue. If Soviet ships had been beyond recall, the blockade would have been a preparation for inevitable engagement; with modern communications the ships were not beyond recall, and the Russians were given the last clear chance to turn aside. Physically the Navy could have avoided an encounter; diplomatically, the declaration of quarantine and the dispatch of the Navy meant that American evasion of the encounter was virtually out of the question. For the Russians, the diplomatic cost of turning freighters around, or even letting one be examined, proved not to be prohibitive.
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There is another characteristic of compellent threats, arising in the need for affirmative action, that often distinguishes them from deterrent threats. It is that the very act of compliance—of doing what is demanded—is more conspicuously compliant, more recognizable as submission under duress, than when an act is merely withheld in the face of a deterrent threat. Compliance is likely to be less casual, less capable of being rationalized as something that one was going to do anyhow. The Chinese did not need to acknowledge that they shied away from Quemoy or Formosa because of American threats, and the Russians need not have agreed that it was NATO that deterred them from conquering Western Europe, and no one can be sure. Indeed, if a deterrent threat is created before the proscribed act is even contemplated, there need never be an explicit decision not to transgress, just an absence of any temptation to do the thing prohibited. The Chinese still say they will take Quemoy in their own good time; and the Russians go on saying that their intentions against Western Europe were never aggressive.
The Russians cannot, though, claim that they were on the point of removing their missiles from Cuba anyway, and that the President’s television broadcast, the naval quarantine and threats of more violent action, had no effect.
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If the object is actually to impose humiliation, to force a showdown and to get an acknowledgement of submission, then the “challenge” that is often embodied in an active compellent threat is something to be exploited.
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Skill is required to devise a compellent action that does not have this self-defeating quality. There is an argument here for sometimes not being too explicit or too open about precisely what is demanded, if the demands can be communicated more privately and noncommittally. President Johnson was widely criticized in the press, shortly after the bombing attacks began in early 1965, for not having made his objectives entirely clear. How could the North Vietnamese comply if they did not know exactly what was wanted? Whatever the reason for the American Administration’s being somewhat inexplicit—whether it chose to be inexplicit, did not know how to be explicit, or in fact was explicit but only privately—an important possibility is that vague demands, though hard to understand, can be less embarrassing to comply with.
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Not enough is known publicly to permit us to judge this Vietnamese instance; but it points up the important possibility that a compellent threat may have to be focused on results rather than contributory deeds, like the father’s demand that his son’s school grades be improved, or the extortionist’s demand, “Get me money. I don’t care how you get it, just get it.” A difficulty, of course, is that results are more a matter of interpretations than deeds usually are. Whenever a recipient of foreign aid, for example, is told that it must eliminate domestic corruption, improve its balance of payments, or raise the quality of its civil service, the results tend to be uncertain, protracted, and hard to attribute. The country may try to comply and fail; with luck it may succeed without trying; it may have indifferent success that is hard to judge; in any case compliance is usually arguable and often visible only in retrospect.
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The Japanese surrender of 1945 was marked as much by changes in the structure of authority and influence within the government as by changes in attitude on the part of individuals. The victims of coercion, or the individuals most sensitive to coercive threats, may not be directly in authority; or they may be hopelessly committed to non-compliant policies. They may have to bring bureaucratic skill or political pressure to bear on individuals who do exercise authority, or go through processes that shift authority or blame to others. In the extreme case governing authorities may be wholly unsusceptible to coercion—may, as a party or as individuals, have everything to lose and little to save by yielding to coercive threats—and actual revolt may be essential to the process of compliance, or sabotage or assassination. Hitler was uncoercible; some of his generals were not, but they lacked organization and skill and failed in their plot. For working out the incentive structure of a threat, its communication requirements and its mechanism, analogies with individuals are helpful; but they are counterproductive if they make us forget that a government does not reach a decision in the same way as an individual in a government. Collective decision depends on the internal politics and bureaucracy of government, on the chain of command and on lines of communication, on party structures and pressure groups, as well as on individual values and careers. This affects the speed of decision, too.
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Second, if the object is to induce compliance and not to start a spiral of reprisals and counteractions, it is helpful to show the limits to what one is demanding, and this can often be best shown by designing a campaign that distinguishes what is demanded from all the other objectives that one might have been seeking but is not.
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The ideal compellent action would be one that, once initiated, causes minimal harm if compliance is forthcoming and great harm if compliance is not forthcoming, is consistent with the time schedule of feasible compliance, is beyond recall once initiated, and cannot be stopped by the party that started it but automatically stops upon compliance, with all this fully understood by the adversary.
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Turning off the water supply at Guantanamo creates a finite rate of privation over time. Buzzing an airplane in the Berlin corridor does no harm unless the planes collide; they probably will not collide but they may and if they do the result is sudden, dramatic, irreversible, and grave enough to make even a small probability a serious one.
The creation of risk—usually a shared risk—is the technique of compellence that probably best deserves the name of “brinkmanship.”
Thomas Schelling explains the dynamics of mutual alarm in Arms and Influence: 
