Schelling's phrase "brute force" receives no easier reception. Here, the problem is rather easy to understand since the phrase itself quickly conjures up images of indiscriminate and primal violence - a kind of warfighting that lies in direct opposition to the institutional identity of modern military professionals.
Military culture and identity thus prevent many practitioners from embracing a body of theory that offers them crucial insights into the nature and practice of their own profession. Understanding coercion is central to developing and implementing sound strategy. When practitioners (either military or civilian) remain innocent of or resistant to coercion theory, they fail to grasp the logic that animates their own decisions and strategies and to understand the ways that their enemies may resist and thwart them, even when those enemies are materially weaker. It also causes them to misunderstand the history of much of the U.S. military experience, especially since World War II. Most importantly, it causes practitioners to systematically overestimate their own chances for quick and low-cost victories.
Another stumbling block to the full use of coercion theory by practitioners is that scholars who write about the topic do not always use consistent terms, definitions, and categories. In some cases, the failure of contemporary scholars to invest sufficient time in Schelling's original texts have resulted in errors that have muddied the theoretical waters. It does not help that Schelling himself wrote in an idiosyncratic way that is not readily grasped by those who do not have the luxury of devoting extensive periods of time to his work. Students in civilian programs of extended duration have this luxury. Students in rather more hurried professional military education programs do not.
The latter sentence is especially problematic, revealing the root of several U.S. failures. A coercer may perceive that a contested stake is "limited," but the state being coerced (i.e., the target state) may not see it that way at all. U.S. efforts to coerce the North Vietnamese in the 1960s were thwarted when the latter turned the tables and ultimately
coerced the United States by raising the price of victory higher than the Americans were willing to pay. To civilian ears, "erosion" sounds vague and underspecified, while "annihilation" suggests something more dramatic than dispensing with the need for enemy cooperation. Both terms leave room for miscommunication.
Military culture and identity thus prevent many practitioners from embracing a body of theory that offers them crucial insights into the nature and practice of their own profession.
To help address this ongoing terminological confusion, this essay seeks to clarify, systematize, and make readily accessible the language of coercion theory. Drawing on Schelling's original texts, I explain the categories he used and the terms he developed. Throughout, I emphasize Schelling's fundamental point: Coercion is difficult, even for actors who hold a preponderance of coercive leverage in a given situation. Schelling and those who have further developed his ideas worked hard to demonstrate that coercion is anything but simple, straightforward, or formulaic. It is not a silver bullet. Indeed, much of the motivation of Schelling's 1966 effort was to explain the complexity of coercion and to provide insights into the challenges one should expect when employing it.
Threats, Influence, and Behavior
Schelling was interested in the ability of military power to "hurt" the enemy - to inflict pain or punishment - and the inherent "bargaining power" this confers. Coercion is about future pain, about structuring the enemy's incentives so that he behaves in a particular way. It manipulates the power to hurt and involves making a threat to do something one has not yet done. The coercer forces another actor to calculate, to decide - based on his own interests and position - whether or not to resist the threat being made.
Similarly, if we wish to keep our homes safe from intruders, we may install a security system and then post a sign advertising it. A potential intruder is alerted to the negative consequences that will greet any attempt to enter without permission. This action is meant to
deter - to prevent someone from taking an action he otherwise might take. But threats can be used to
compel actions as well as deter them. In the film
The Godfather, Don Corleone promises to influence the decisions of the head of a film studio, stating, "I'm gonna make him an offer he can't refuse." If the recipient of the threat refuses to accept the "offer" (which is actually a demand), then harm will follow. The coercive threat is designed to compel an individual to do something he would prefer not to do. If the threat derives from a source known to be willing and able to produce harm, then it is credible and must be taken seriously.
Political actors use coercive threats all the time to protect themselves and to preserve and promote their interests. Schelling observed,
Deterrence, Compellence, and Brute Force: Definitions
[T]he central characteristic of both forms of coercion is that they depend, ultimately, on cooperation by the party receiving the threat. This is by no means friendly cooperation, but it is cooperation nonetheless.
Land power plays a particularly important role in the realm of brute force/forcible action. If an army can control the situation on the ground, it ultimately can dispense with seeking an adversary's cooperation. If it is strong enough, an army can remove an existing government and replace it with one that is more congenial to the political authorities it serves, and then control the aftermath. This is demanding and costly, and is therefore typically reserved for extreme situations. Of course, armies have many roles short of using brute force/forcible action. Indeed, their existence affords decision-makers a critical tool for deterrence and compellence. However, their role as agents of brute force/forcible action is crucially important. It is thus vital for students of military power to understand the logical distinction between Schelling's primary categories of coercion and brute force/forcible action, and the strengths and weaknesses of both. And it is equally important for civilian authorities to understand the ways in which different military instruments relate to them.
Methods of Coercion
Actors can deter by threat of punishment or by threat of denial. The meaning of the first is easy to discern: The coercing state threatens to impose pain on the target state for failure to comply with the coercer's demand. This might involve an air strike on a location valued by the target state or a naval blockade to deny it crucial resources. Perhaps the most familiar version of deterrence since the advent of the Cold War is nuclear deterrence. Nuclear weapons certainly are not necessary to inflict punishment, but, as Schelling pointed out, no weapon has ever surpassed nuclear weapons for threatening severe pain.
Deterrence is a strategy for combining two competing goals: countering an enemy and avoiding war. Academics have explored countless variations on that theme, but the basic concept is quite simple: an enemy will not strike if it knows the defender can defeat the attack, or can inflict unacceptable damage in retaliation.
It is an actor's will and determination (to gain or hold a stake), rather than its raw power - defined in physical, military, or economic terms - that usually dictates the outcome in a coercive interaction.
Punishment and denial come into play in compellence as well. Airpower, particularly 21st-century airpower, is often viewed as a coercive tool of choice since it is easily scaled and tailored, and can be used by some air forces, including the U.S. Air Force, with high precision against discrete targets. Air strikes can, at once, inflict pain and signal an intention to inflict future pain. In a denial role, they can interdict military supplies and destroy key military infrastructure, preventing an adversary from fighting effectively.
Characteristics of Coercive Threats: Distinctions and Requirements
The two main categories of coercion - deterrence and compellence - are distinct in their nature and requirements. When an actor refrains from a behavior, one does not and cannot know the specific reason (or reasons) for that choice. Refraining from an action can be attributed to causes other than the specific deterrent threat. The enemy may never have intended to attack in the first place, for example, in which case the deterrent threat is not what prevented the attack. In fact, it is
never clear whether the absence of an attack is due to an enemy giving in to a deterrent threat. This ambiguity enables enemies who have been deterred to save face.
Coercive action often begins with economic action - the freezing of assets, perhaps, or the imposition of sanctions. The goal is to force the target state (or actor) to choose between conceding the disputed stake or suffering future pain that making such a concession would avert. The target state must be convinced that if it resists it will suffer, but if it concedes it will not. If it suffers either way, or if it has already suffered all it can, then it will not concede and coercion will fail.
Communication by the coercer may be verbal, but it need not be. It can also be delivered through
an action itself. Schelling argued:
Precision of thought and language can matter greatly in compellence, while a degree of vagueness occasionally can be useful for deterrence.
In the case of deterrence, a nation's willingness to defend its own sovereign territory is typically clear. Its willingness to defend another's territory - or to risk drawing pain upon itself for the sake of another - is not as certain. Schelling explained:
Airpower and Coercion
Pape's argument - that aerial coercion is not simple or easy, and that punishment is less effective than most people expect - was important, and over the years has been influential. But Pape did not look in detail at the role of land power and the way it can work as a central element of denial and an essential component of brute force. His analysis, though important, captures only part of the picture. There is a need for further investigations into the way denial actually works in terms of the interplay between air, sea, and ground forces.
In general, air forces and navies can impose punishment and can aid denial in myriad ways. Navies can prevent an adversary from receiving crucial supplies needed to fight, while air forces can seek to interdict supplies, both strategically and operationally. At a basic level, ground forces in expeditionary campaigns cannot reach their destinations alone: They must be transported to the location where they will fight. Furthermore, they rely on their sister services for a steady supply of the equipment and materiel that allows them to fight. Navies thus seek sufficient control of the sea lanes to maintain routes for transportation and communications.
Escalation Dominance and the Role of Brute Force
What practitioners must understand is that escalation dominance is not just a matter of having better technology or more resources. War is a contest of wills as much as it is a contest of instruments and materiel. Once an actor has entered into coercive activity he must be prepared to go forward, matching the adversary's resistance
in determination as well as in capability. Again, this requires that the coercer have considerable insight into not only his own commitment to a stake, but his adversary's as well. And it may require the coercer to climb the escalatory ladder longer than he would have predicted or preferred.
[A]ny state that wants to protect and preserve global interests must possess, and be prepared to use, sophisticated forms of expeditionary land power.
While armies are powerful tools, their use is accompanied by some significant risks and drawbacks, even when the deployment is for something as seemingly straightforward as humanitarian assistance. Moving and using an army is costly in terms of time, treasure, and, sometimes, blood. The use of land power comes with strings attached that do not usually accompany discrete uses of air and naval power in independent coercive actions. An army's presence on the ground is at once its greatest strength and its greatest weakness. Deploying an army is, first of all, obvious: It signals a commitment that cannot be shrugged off later without humiliation and, perhaps, costs to one's credibility. The use of an army also does not guarantee success. A determined weaker enemy may be willing to enter an escalatory contest, upping the ante by turning to irregular methods and relying on time (and a high pain threshold) to hold out against a stronger force. Or it may turn to irregular methods once a conventional war has been fought, in order to shift the terms of surrender or alter the postwar political situation.
The Ongoing Utility of Coercion Theory
National security practitioners need to have a strong grasp of coercion theory if they are to be effective strategists and warfighters. The value of deterrence in particular has been lost among those worrying about threats in realms where deterrence is difficult, such as terrorism and cyber attacks. But deterrence remains an invaluable asset for national security. In the 21st century, it must be updated and applied intelligently to a new landscape of threats and challenges. Yet this hardly means that all we know about deterrence from its long history is suddenly obsolete. If there is a tendency in the Defense Department to think that technology so changes the landscape of war that the past no longer applies, then it is a pernicious tendency that works to America's disadvantage. As Clausewitz insisted, wars will change in character over time, but their essential nature does not.
It is equally important to ensure - to the greatest extent possible - that any attempts America makes to deter an adversary are not interpreted as offensive or provocative.
Such creative thinking, however, depends on a solid understanding of coercion theory. For strategists, this body of literature is crucial. It forces planners and decision-makers to think through the assumptions and the logic of their actions. And it pushes them away from the dangerous idea that material power or predominance guarantees victory in conflict. The promise of a quick return on a coercive action can be a dangerous siren song for decision-makers looking for a simple solution to a complex political problem. In any scenario involving potential conflict, military and intelligence professionals need to anticipate challenges and problems and convey them effectively and persuasively.
Finally, an understanding of coercion theory helps all students of strategy appreciate the timelessness of the writings of strategists like Sun Tzu and Clausewitz, who warned about the need to make careful assessments, not only of our enemy but of ourselves. We must understand whether the stake in a given contest is more valuable to us or to the enemy. And we must face, with honesty and sobriety, the likely cost of our choices in money, time, and blood.
Tami Davis Biddle
is professor of history and national security at the U.S. Army War College in Carlisle, Pennsylvania. She writes frequently on airpower, grand strategy, and 20th- and 21st-century warfare. She is the author, recently, of
Strategy and Grand Strategy: What Students and Practitioners Need to Know
(Strategic Studies Institute, 2015), and "On the Crest of Fear: The V-Weapons, the Battle of the Bulge, and the End of War in Europe, 1944-1945," in the Journal of Military History
(January 2019).
This article reflects the views of the author. It does not necessarily represent the views of the U.S. Army or Department of Defense.
Acknowledgements
: I am grateful to colleagues who offered ideas and helpful comments on earlier drafts of this essay, including Conrad Crane, Darrell Driver, Edward Kaplan, Michael Neiberg, Celestino Perez, James Powell, Marybeth Ulrich, and Doug Winton. Stephen Biddle has influenced my thinking on this topic for years.