Coercion Theory: A Basic Introduction for Practitioners

While coercion theory may be well understood in the academy, it is less well understood by practitioners, especially in the military. This can cause difficulties in civil-military communications and cause problems for national strategy and military outcomes. In this essay, Tami Davis Biddle clarifies, systematizes, and makes more readily accessible the language of coercion theory.

1. Arms and Influence (New Haven, CT: Yale University Press, 2008, reprint of the original 1966 edition). Thomas Schelling (1921-2016) taught in the economics department at Yale at the beginning of his career, and then moved to the economics department at Harvard. He also served in the government and worked for the RAND Corporation. He ended his career at the University of Maryland. In 2005, he won the Nobel Prize in Economics. See, William Grimes, "Thomas Schelling, Master Theorist of Nuclear Strategy, Dies at 95," New York Times, Dec. 13, 2016, https://www.nytimes.com/2016/12/13/business/economy/thomas-schelling-dead-nobel-laureate.html.
2. 2 Other contributors in this early era included: J. David Singer, Glenn Snyder, Morton Kaplan, William Simons, George Quester, Bernard Brodie, Henry Kissinger, Albert Wohlstetter, and Herman Kahn.
3. 3 Key contributors and critics include: Robert Jervis, Richard K. Betts, John Mearsheimer, Barry Posen, Lawrence Freedman, Richard Ned Lebow, Janice Stein, Patrick Morgan, Richard Smoke, Alexander George, Robert Art, Charles Glaser, Scott Sagan, Robert Powell, Stephen Van Evera, Robert Pape, Bruce Russett, Paul K. Huth, Wallace Thies, Daniel Byman, Matthew Waxman, Patrick Cronin, Darryl Press, Alexander Downes, Todd Sechser, and Austin Long. Writers including Martin Libicki, Jon R. Lindsay, and Erik Gartzke have begun to look hard at deterrence in the cyber realm.
4. 4 These observations are generalizations that rest largely on my many years of experience as a scholar responsible for teaching practitioners.
5. 5 Here coercion theory also intersects with the bargaining theory of war, associated with scholars including James Fearon, Donald Wittman, Dan Reiter, Harrison Wagner, Suzanne Werner, and Geoffrey Blainey.
6. Joint Publication 1: Doctrine for the Armed Forces of the United States, Joint Chiefs of Staff, March 25, 2013 (Incorporating Change 1, July 12, 2017), I-4, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp1_ch1.pdf.
7. Joint Publication 1: Doctrine for the Armed Forces of the United States, I-4. If the military were to accept the terms generally used in the scholarly debate, they could communicate more easily with civilians trained in the field of national security, and could more readily tap into the broad and useful body of literature that has developed in the wake of Schelling's original work.
8. Joint Publication 3.0: Joint Operations, Joint Chiefs of Staff, chap. VI, Campaigning Through Cooperation and Competition, sec. III.
9. Joint Doctrine Note 2-19: Strategy, Joint Chiefs of Staff, Dec. 10, 2019, II-4-II-5. For quoted material, see, I, https://www.jcs.mil/Portals/36/Documents/Doctrine/jdn_jg/jdn2_19.pdf?ver=2019-12-20-093655-890. (Readers should not confuse U.S. Joint Doctrine Note 2-19 with the U.K. Ministry of Defence JDN 2/19 of April 2019).
10. Foreign Affairs 92, no. 2 (March/April 2013), https://www.foreignaffairs.com/articles/united-states/2013-02-11/lost-logic-deterrence. Paul Bracken emphasizes that, in the current threat environment, the role of nuclear weapons in deterrence must be understood - as well as their role in communication and bargaining. See, Paul Bracken, The Second Nuclear Age: Strategy, Danger, and the New Power Politics (New York: St. Martin's Griffin, 2013), esp. 61.
11. Arms and Influence, he refers to the influence of parents over their children on a number of occasions. See, for instance, pages 74 and 136.
12. Arms and Influence, xiii.
13. Arms and Influence, xiii-xiv.
14. Arms and Influence, 2.
15. Arms and Influence) refers to hostages and hostage-taking on multiple occasions. See, for instance, pages 6 and 8.
16. Deterrence (Cambridge, UK: Polity Press, 2004), 1.
17. Arms and Influence, 70-71. See also Schelling's preface to the 2008 reprinted edition, x. Robert J. Art and Kelly M. Greenhill point out that naming and categorization conventions have not been consistent in the literature: "Often the terms coercion and compellence are used interchangeably, but that erroneously implies that deterrence is not a form of coercion." In their own work, they have chosen to stay with Schelling's original categorization. See, Robert J. Art and Kelly M. Greenhill, "Coercion: An Analytical Overview" in Coercion: The Power to Hurt in International Politics, ed. Kelly M. Greenhill and Peter Krause (New York: Oxford University Press, 2018), 5.
18. American Political Science Review 57, no. 2 (June 1963): 420-30, https://doi.org/10.2307/1952832. Schelling found the related adjective "persuasive" problematic since it "is bound to suggest the adequacy or credibility of a threat, not the character of its objective." See, Schelling, Arms and Influence, 71, note 17. It is clear that Singer's work informed Schelling and inspired him to further efforts.
19. Arms and Influence, 69 and 71. Italics added by this author.
20. Arms and Influence, 70.
21. Forceful Persuasion: Coercive Diplomacy as an Alternative to War (Washington, DC: US Institute of Peace Press, 1991).
22. Coercion: The Power to Hurt in International Politics, ed. Greenhill and Krause, 96.
23. 24 Other frequent users in history have been Japan, Germany, Great Britain, and Russia. See, Downes, "Step Aside or Face the Consequences," 93-114, esp. 112.
24. The Economic Diplomacy of the Suez Crisis (Chapel Hill: University of North Carolina Press, 1991); "The Suez Crisis, 1956," Office of the Historian, Department of State, https://history.state.gov/milestones/1953-1960/suez. On Mexico, see, Tracy Wilkinson and Noah Bierman, "US and Mexico Strike a Deal on Migration, Staving off Trump's Tariff Plan," Los Angeles Times, June 7, 2019, https://www.latimes.com/nation/la-na-pol-us-mexico-tariffs-immigration-talks-20190607-story.html.
25. 26 Downes writes, "Studies of compellence in international relations confirm Thomas Schelling's argument that success is elusive." See, Downes, "Step Aside or Face the Consequences," 97, also 93. See also, Art and Greenhill, who offer a useful summary of the reasons why coercion is difficult, in "Coercion, An Analytical Overview,"18-19.
26. Security Studies 16, no. 2 (2007): 163­-88, https://doi.org/10.1080/09636410701399440.
27. Dr. Strangelove.
28. Strategic Studies Quarterly 12, no. 4 (Winter 2018): 78-79, https://www.jstor.org/stable/26533616. Italics added by this author.
29. Perception and Misperception in International Politics (Princeton, NJ: Princeton University Press, 1976); but Jervis is a prolific contributor with an extensive body of work on this topic.
30. International Security 7, no. 3 (Winter 1982/1983), reprinted in Steven. E. Miller, Strategy and Nuclear Deterrence (Cambridge, MA: MIT Press, 1984), 57-84; and Robert Jervis, Richard Ned Lebow, and Janice Gross Stein, Psychology and Deterrence (Baltimore: Johns Hopkins University Press, 1985).
31. Arms and Influence, esp. xiv, 2, and 3 for quoted material. "Forcible action" appears on page 80.
32. Arms and Influence, 4 and 3. On page 8, Schelling adds, importantly, "Brute force can only accomplish what requires no collaboration."
33. Arms and Influence, 1-3. For quoted material see page 1.
34. Arms and Influence, 8-9. Note, too, that terror campaigns are coercive in that any given terrorist act (and the destruction it produces) is less important than the fear it raises about repeat (and perhaps escalated) acts. What is important for the strategist to focus on and prioritize is the intention and logic guiding his or her campaign.
35. Bombing to Win: Air Power and Coercion in War (Ithaca, NY: Cornell University Press, 1996), 18, 29-35, 69-79.
36. 37 Betts, "The Lost Logic of Deterrence," 88.
37. 38 But "will" is a slippery term since it is hard to measure (either in isolation or in comparison). This is another element explaining the challenge and difficulty inherent in coercion.
38. On Limited Nuclear War in the 21st Century, ed. Jeffrey A. Larsen and Kerry M. Kartchner (Stanford, CA: Stanford University Press, 2014), 109.
39. and to deny. With regard to the latter, the denial would come in the form of eroded command and control. For insights, see, Pape, Bombing to Win, 211-53.
40. The United States and Coercive Diplomacy, ed. Robert J. Art and Patrick Cronin (Washington, DC: United States Institute of Peace Press, 2003), 362. Also Schelling, Arms and Influence, 82-84.
41. 42 Downes, "Step Aside or Face the Consequences," 99.
42. Arms and Influence, 72.
43. Arms and Influence, 73. See also page 75 where he states, "There is a tendency to ... give too little emphasis to communicating what behavior will satisfy us."
44. Coercion: The Power to Hurt in International Politics, ed. Greenhill and Krause, 33-54.
45. Arms and Influence, 3-4.
46. 47 Here though, actors need to be careful. Any threat that is underspecified and can confuse the target state (potentially leading to miscommunication) should be avoided.
47. Bureaucratic Politics and Foreign Policy (Washington, DC: Brookings Institution, 1974); Robert Jervis, "Deterrence Theory Revisited," Center for Arms Control and Security Working Paper, no. 14 (1978); Scott D. Sagan and Kenneth N. Waltz, The Spread of Nuclear Weapons: A Debate Renewed (New York: W.W. Norton, 2003).
48. Arms and Influence, 3.
49. Planners Handbook for Operational Design, Version 1.0, Joint Staff J-7, Oct. 7, 2011, https://www.jcs.mil/Portals/36/Documents/Doctrine/pams_hands/opdesign_hbk.pdf.
50. The Dynamics of Coercion: American Foreign Policy and the Limits of Military Might (Cambridge, UK: Cambridge University Press, 2002), 18.
51. Arms and Influence, 36.
52. The Evolution of Nuclear Strategy (New York: St. Martins, 1981).
53. Arms and Influence, 49-50 (quoted material on page 50).
54. The First World War: A Very Short Introduction (New York: Oxford University Press, 2002), 88.
55. Bombing to Win is now read widely by those seeking to understand airpower and coercion.
56. 57 On this issue see, Art and Greenhill, "Coercion, An Analytical Overview," 21. Schelling himself had no "risk" category distinct from "punishment."
57. 58 The leading proponent of decapitation was Col. John Warden of the U.S. Air Force, who placed "leadership" in the center of his now-famous five targeting rings.
58. Rhetoric and Reality in Air Warfare (Princeton, NJ: Princeton University Press, 2004), 270-78. Here I refer to the firebombing of Japan taking place between March and August 1945. The two nuclear attacks require a different analysis.
59. intent of the act; 2) of the way that airpower is operating on the target state; and 3) of the way it is interacting with other elements of military and nonmilitary power.
60. Challenges to Security in Space, Defense Intelligence Agency, 2019, https://www.dia.mil/Portals/27/Documents/News/Military%20Power%20Publications/Space_Threat_V14_020119_sm.pdf; Joint Publication 3-12: Cyberspace Operations, Joint Chiefs of Staff, June 8, 2018, https://www.jcs.mil/Portals/36/Documents/Doctrine/pubs/jp3_12.pdf; Sandeep Baliga, Ethan Bueno de Mesquita, and Alexander Wolitzky, "The Case for a Cyber Deterrence Plan that Works," National Interest, March 5, 2019, https://nationalinterest.org/feature/case-cyber-deterrence-plan-works-46207.
61. The Dynamics of Coercion, 38-39.
62. The Dynamics of Coercion, 100.
63. The Dynamics of Coercion, 101.
64. Fortissimus Inter Pares: The Utility of Land Power in Grand Strategy," Parameters 42, no. 2 (Summer 2012): esp. 10.
65. Army 56, no. 5 (May 2006): 9-14. For quoted material, see page 10. (Italics added by this author.) In the same essay he explains, "Winning wars against determined enemies will always require eliminating the enemy's option to decide how and when the war ends." See page 11.
66. intent of a land campaign (from the outset) is brute force, it will be coercive initially: The target state has, after all, the option to concede at any point, and may do so early if the handwriting is on the wall.
67. War and the Art of Governance: Consolidating Combat Success into Political Victory (Washington, DC: Georgetown University Press, 2017).
68. 69 There are, of course, examples of wars that were relatively short and relatively inexpensive for one side. The Franco-Prussian War (for the Prussians) and the Falklands War (for the British) come to mind. But short and inexpensive wars have not been the norm in history. Many a state that has banked on such an outcome has been sorely disappointed.
69. 70 Here I am relying on language suggested to me by Dr. Richard Lacquement, dean of the School of Strategic Landpower at the U.S. Army War College.
70. 71 The need to reassure domestic audiences about costs is the main reason why some U.S. presidents have moved toward conflict while simultaneously indicating that ground force will be ruled out. This approach, however, undermines the powerful threat inherent in land power, and thus erodes escalation dominance.
71. Improving Strategic Competence: Lessons from 13 Years of War (Arlington, VA: RAND Arroyo Center, 2014), www.rand.org/content/dam/rand/pubs/research_reports/RR800/RR816/RAND_RR816.pdf; Tami Davis Biddle, "Making Sense of the 'Long Wars' - Advice to the US Army," Parameters 46, no. 1 (Spring 2016): 7-11.
72. American Force: Dangers, Delusions, and Dilemmas in National Security (New York: Columbia University Press, 2012), 3-18. On civil-military relations in particular, see pages 201-31.
73. The Sword's Other Edge: Trade-offs in the Pursuit of Military Effectiveness, ed. Dan Reiter (Cambridge, UK: Cambridge University Press, 2017), 197-226.
74. 75 See, Betts, "The Lost Logic of Deterrence," 95.
75. 76 Betts, "The Lost Logic of Deterrence," 88, 92, 96-99.
76. Understanding Global Conflict and Cooperation: An Introduction to Theory and History, 8th ed. (New York: Longman, 2011), 17-18,
77. Arms and Influence, 77-78. Alexander George, Forceful Persuasion, 31-38.
78. fait accompli. See, Dan Altman, "Advancing Without Attacking: The Strategic Game around the Use of Force," Security Studies 27, no. 1 (2018), 58-88, https://doi.org/10.1080/09636412.2017.1360074.
79. Arms and Influence.1 An economist by training, Schelling developed his early work at a time when debates over nuclear strategy dominated the landscape, although his work is applicable to all varieties of force.2 Over the past 50 years, scholars have embraced and built upon Schelling's work, using it to shed light on an array of issues in defense and national security.3 If coercion theory is understood in the academy, however, it is less well understood by practitioners, especially those in the military. This is a problem for civil-military communication, and, more generally, for national strategy and military outcomes.
80. cooperation of the enemy. Even if one explains that this is by no means happy cooperation, it rankles nonetheless because they (especially those in the U.S. military) believe they should own the initiative and maintain dominance across the full spectrum of conflict at all times.4
81. The word "coercion" itself sits uneasily with military professionals. It has overtones of blackmail and manipulation, which are anathema to their self-identity. In general, they also do not take readily to Schelling's emphasis on threats. While they fully understand deterrence, they may draw back from the idea that they are in the business of "threatening" others (and sometimes making those threats credible by actions) in order to deter and compel. For Schelling, conflicts involving coercion unfold through a kind of violent communication about intentions and commitment. Understandably, few military officers see killing and dying as just a form of communication.5
82. Doctrine for the Armed Forces of the United States, explains that there are "two fundamental strategies" in the use of military force: "annihilation" and "erosion."6 The first term corresponds roughly to Schelling's "brute force," and the second corresponds roughly to "coercion," although the parallels in each case are imperfect. Annihilation seeks "to make the enemy helpless to resist us, by physically destroying his military capabilities. ...It requires the enemy's incapacitation as a viable military force." Erosion, by contrast, seeks "to convince the enemy that accepting our terms will be less painful than continuing to aggress or resist." Its goal is to erode "the enemy leadership's or the enemy society's political will." With erosion, military force is employed "to raise the costs of resistance higher than the enemy is willing to pay." The authors of the doctrine argue that erosion is used "in pursuit of limited political goals that we believe the enemy leadership will ultimately be willing to accept."7
83. A new version of Joint Publication 3.0, currently in draft, not only confuses Schelling's categories, but uses his term "compellence" (which is a subset of coercion), to describe what Schelling called "brute force." If adopted, this publication will flip the meaning of two of Schelling's most important terms, putting the military's doctrinal categories dramatically at odds with the civilian literature on coercion theory. Given that doctrine ought to be a starting place for military thought and a mechanism for civil-military communication, this revision could have serious ramifications.8 On the other hand, the recent Joint Doctrine Note 2-19 (published in December 2019) uses the language of coercion theory accurately and is thus a welcome change. While a joint doctrine note does not supersede existing doctrine, it "facilitates information sharing on problems and potential solutions to support formal doctrine development and revision."9 This new publication moves in the right direction.
84. faits accomplis and by working around red lines. The Joint Staff have made "deterrence theory" a special area of emphasis for professional military education in the immediate future,11 but the utility of such a move will rest on a shared understanding of terms and concepts among scholars and practitioners.
85. Observing human behavior, Schelling recognized that humans use threats constantly to shape the behavior of others. We do this for a range of reasons. Anyone who has raised a child has learned quickly how to influence that child's choices: A parent may issue a threat in order to keep a child from harm, or to set boundaries to help prepare the child for civil interaction with others. As children grow older, the content of those behavior-influencing threats must change in order to reflect the child's level of comprehension and new interests and the parent's changing leverage over the child's behavior.12
86. actor's hands. This is what makes coercion difficult and complex - and distinct from a more direct use of power that Schelling defined as "brute force," wherein there is no need for a decision by the target state because power is imposed directly in such a way as to obviate choice.
87. The bargaining power that comes from the physical harm a nation can do another nation is reflected in notions like deterrence, retaliation, reprisal, terrorism, and wars of nerve, nuclear blackmail, armistice and surrender, as well as in reciprocal efforts to restrain that harm in the treatment of prisoners, in the limitation of war, and in the regulation of armaments.14
88. The power to hurt confers bargaining power, Schelling insisted. The willingness to exploit it is diplomacy - "vicious diplomacy, but diplomacy."15
89. Schelling explained that the use of "the power to hurt" operates like blackmail in that it exploits an enemy's fears and needs. The power to hurt is usually most successful when it is held in reserve. Hostages, for instance, are taken and held for coercive purposes. Those taking the hostages seek to make another actor give up something - money, political prisoners, etc. But if they kill the hostage, the other actor no longer has an incentive to concede and coercive hostage-taking fails. Any coercive act that kills the hostage, as it were, reduces its own effectiveness. Hostages, Schelling argued, "represent the power to hurt in its purest form."16
90. Arms and Influence.17 The term "compellence" he coined himself, after rejecting several alternatives. Since 1966, it has become part of the lexicon of security studies.18 (Schelling admired, but chose not to select, the terms "dissuasion" and "persuasion" that J. David Singer had used several years earlier to describe a similar idea.)19
91. do something."20 In deterrence, the punishment will be imposed if the adversary acts; in compellence, the punishment is usually imposed until the adversary acts.21 As noted, the 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. Compellence can be used in peacetime and in wartime, the former use being referred to generally as coercive diplomacy.22
92. Alexander Downes describes coercion as "the art of manipulating costs and benefits to affect the behavior of an actor." Explaining its two forms, he writes, "Deterrence consists of threats of force designed to persuade a target to refrain from taking a particular action. Compellence, by contrast, utilizes force - or threats of force - to propel a target to take an action, or to stop taking an action it has already started."23 The United States, he notes, is one of the most frequent users of compellent threats.24 Examples abound. Sometimes they involve the use (or threatened use) of U.S. troops, and sometimes they do not. But military power always stands in the background. In one notable example from 1956, President Dwight Eisenhower used economic and diplomatic threats to compel the British, French, and Israelis to cease the military operations they had begun in response to Egypt nationalizing the Suez Canal. More recently, the administration of President Donald Trump used a threat of economic sanctions to try to compel the Mexican government to more aggressively discourage population flows across the U.S. border.25
93. As a major power seeking to maintain the existing international structure, the United States possesses coercive leverage and uses it over other states. A sense of its own power, combined with a desire to use that power to solve complex problems with minimum trouble and expenditure, has inclined American decision-makers to look to coercion repeatedly. But coercion, especially compellence, is difficult, and provides no guarantee of success - not even to very powerful actors.26 Reviewing five empirical studies of coercion, Downes concludes that compellence succeeds only about 35 percent of the time.27
94. in the mind of the potential aggressor."28 Moreover, he observes that because the future is uncertain and difficult to predict, states often make choices based on misperception - and those choices sometimes involve entering into ill-advised wars. 29
95. Robert Jervis's work elaborates in detail how and why two actors may perceive (and respond to) the same situation very differently.30 He insists that decision-makers and analysts ask some key questions about coercion, including: Do the adversaries assess the stakes similarly? Do they view the credibility of threats the same way? Are both sides equally concerned about reputation? Jervis points out that cultural norms and expectations vary, perspectives differ, and domestic political imperatives may override other pressures. Opportunities for misperception and miscommunication abound.31
96. Arms and Influence, Schelling took pains to distinguish coercion from "brute force," which, he argues, is used "without [reliance on] persuasion or intimidation." Later in the book, he uses the phrase "forcible action" as a synonym, a preferable phrase because it does not carry so much linguistic baggage.32 With brute force/forcible action there is no need for the opponent's cooperation. The actor simply takes what it wants. Schelling compared this to the way a tank or a bulldozer can simply "force its way, regardless of others' interests." Brute force, he explained, "is concerned with enemy strengths, not enemy interests."33 Adding detail to the idea, Schelling wrote: "Forcibly a country can repel and expel, penetrate and occupy, seize, exterminate, disarm, and disable, confine, deny access, and directly frustrate intrusion or attack." Brute force is directly measurable and is usually measured relative to an enemy's strength, the one opposing the other.34 Unlike coercion, brute force/forcible action does not place the outcome in the hands of the adversary.35
97. deny the ability to complete the action successfully.36 Richard K. Betts offers a definition of deterrence notable for its lucidity and conciseness:
98. Here Betts refers first to deterrence by threat of denial ("can defeat the attack") and then to deterrence by threat of punishment ("can inflict unacceptable damage in retaliation").37 It should be noted here that deterrence and compellence can be used by small states as well as large states. 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.38
99. Deterrence by threat of denial and deterrence by threat of punishment are sometimes linked to one another. For instance, a state may imply to an enemy that if denial fails, it will resort to punishment. In the Cold War era, deterring a Soviet grab for Western Europe involved both threats of denial and threats of punishment. Because NATO had fewer ground forces than the Warsaw Pact, both denial and punishment rested heavily on U.S.-funded and controlled nuclear forces.39 Today, NATO ground forces once again are engaged in exercises designed to sharpen their conventional military skills, and thus to deter Russian action by threat of denial. Still standing in the background, though, is the potential threat of punishment posed by U.S. nuclear weapons.
100. For the practitioner, it is important to understand the fundamental logic being employed so that the strengths and weaknesses of the ways and means utilized will be clear, thus reducing the likelihood of frustration or surprise when the enemy seeks to thwart or resist those ways and means. In 1990, for instance, Operation Desert Shield sent U.S. troops to the Middle East to deter an Iraqi incursion into Saudi Arabia. In January 1991, air strikes against Iraq were used largely to compel Iraq to pull out of Kuwait, while air strikes against Kuwait served mainly to undermine Iraqi capabilities in that theater. If the Iraqis did not concede, then the United States and its allies were committed to an invasion of Kuwait designed to deny Iraq its gains, and, ultimately, to drive the Iraqi army from Kuwait through brute force/forcible action.40
101. perform an act rather than simply refrain from one - it is clear to all when compellence is successful. Moreover, the actor being compelled is usually being forced into some degree of humiliation. Robert Art explains that compellence requires the target state's "overt submission."41 The ability of a powerful state to compel a less powerful one is constrained and complicated by this fact. Coercers, Downes argues, "tend to underestimate the target's concern for its reputation and thus offer too little compensation to obtain the target's acquiescence." He adds, "The target's fear for its reputation and the challenger's unwillingness to lower its demands or offer side payment to compensate the target for the damage to its reputation cause the target to resist threats from powerful states."42 Thus, though the state being coerced may appear to be in a weaker position, this is not true in one important sense: The state being coerced ultimately makes a decision about whether or not to comply - and in that sense it holds the initiative.
102. As Schelling pointed out, when it comes to timing deterrence can be indefinite while compellence, by contrast, must be definite. Without a deadline, the adversary being compelled has no incentive to act: "If the action carries no deadline it is only a posture, or a ceremony, with no consequences." But on the other hand, if too little time is given for compliance, then the coercer has put its adversary into an impossible position, virtually ensuring that compellence will fail. Schelling summed this up by stating, "Too little time and compliance becomes impossible; too much time and compliance becomes unnecessary."43
103. stop the pain if the target state concedes the stake. The promise to cease coercion if the enemy gives in must be believed, just as the threat to continue coercion if the target state withholds the stake must be. When it comes to deterrence, a promise not to attack if the enemy doesn't invade is easier to believe - after all, there is no attack taking place right now. In deterrence, Schelling observed, "the objective is often communicated by the very preparations that make the threat credible." By contrast, compellent threats "tend to communicate only the general direction of compliance, and are less likely to be self-limiting, less likely to communicate in the very design of the threat just what, or how much, is demanded." Offering an example, Schelling focused on the Western military garrison in West Berlin during the Cold War, which, he argued, had an unmistakable deterrent purpose. Were it to intrude into East Berlin, though, "to induce Soviet or German Democratic Forces to give way," there would be no "obvious interpretation" of "where and how much Soviet and East German forces ought to give way unless the adventure could be invested with some unmistakable goal or limitation - a possibility not easily realized."44
104. The centrality of communication means that coercion is heavily dependent on knowledge, and thus on sophisticated intelligence.45 The coercer must understand the target state's fears, vulnerabilities, and interests - as well as its willingness to endure pain on behalf of those interests. For these reasons, coercion is subject to cultural miscommunication while brute force is not. As Schelling explained,
105. To exploit a capacity for hurting and inflicting damage one needs to know what an adversary treasures and what scares him, and one needs the adversary to understand what behavior of his will cause the violence to be inflicted, and what will cause it to be withheld. The victim has to know what is wanted, and he may have to be assured of what is not wanted.46
106. One can thus see the many formidable challenges facing a coercer. Precision of thought and language can matter greatly in compellence, while a degree of vagueness occasionally can be useful for deterrence.47 A nuanced understanding of the needs, fears, capabilities, interests, and will of the target state is essential. But the coercer must possess self-knowledge as well, including an understanding of the importance of the stake involved, and the likely commitment to it - by policymakers and by the domestic population - over time. And the coercer must be able to articulate the demand in ways the target state can comprehend and comply with. To understand all this is to understand the deeper meaning of Carl von Clausewitz's insistence on the linkage between war and politics, and the need to recognize the relationship between the stake and the scale of effort required to achieve it. It is also to understand, beyond a superficial level, the meaning of Sun Tzu's insistence on knowing one's self, and knowing one's enemy.
107. One should note here, too, that democracies engaging in coercion will face a challenge inherent in the structure of their system of governance: Communication is complicated by multiple power centers - built by design to check one another - and myriad interest groups. Indeed, bureaucratic (and organizational) models of decision-making are at the center of many scholars' critiques of U.S. foreign policy, and deterrence in general.48
108. Unhappily, the power to hurt is often communicated by some performance of it. Whether it is sheer terroristic violence to induce an irrational response, or cool premeditated violence to persuade somebody that you mean it and may do it again, it is not the pain and damage itself but its influence on somebody's behavior that matters.49
109. In many instances verbal threats are backed up by actions to ensure that the message is being taken seriously. But the coercer must be sure that language and actions are aligned, clear, and suitably tailored to create the behavior being sought. If miscommunication occurs in any of these realms - due to carelessness, mixed messaging from different groups within the coercing state, or cultural obtuseness - then coercion is likely to fail. Military planners who understand this will have an elevated appreciation for the crucial importance of getting all the details right when they are engaged in the important work of operational design.50 And they will also have a heightened appreciation of the need for a fastidious commitment to inter-agency coordination.
110. Credibility, which matters for deterrence and compellence, is neither unvarying nor permanent. Actors place different values on stakes. This means that adversaries will constantly try to calculate each other's level of interest in and commitment to a given stake. A preponderance of strength does not imply successful coercion. Daniel Byman and Matthew Waxman have observed, "The United States failed to coerce North Vietnam; Russia failed to coerce Chechen guerillas to give up their struggle; Israel has pulled out of Lebanon. These instances ... evince the importance of vital, if rather ineffable factors." They add: "Will and credibility matter as much as, and often more than, the overall balance of forces. At times a coercer may have preponderant power in a general sense but lack specific means to influence an adversary."51
111. fight abroad is a military act, but to persuade enemies or allies that one would fight abroad, under circumstances of great cost and risk, requires more than a military capability. It requires projecting intentions. It requires having those intentions, even deliberately acquiring them, and communicating them persuasively to make other countries behave.52
112. During the Cold War, what came to be called "Mutually Assured Destruction" rested on the idea that a Soviet nuclear attack on the United States would be answered by a U.S. nuclear attack on the Soviet Union, and vice versa.53 Whether the United States would have risked a nuclear strike on its own territory in order to protect Paris or Bonn, however, was not nearly so clear. But U.S. statesmen, through words, policies, and actions, sought to convince their Soviet adversary that the threat was real. In other parts of the world, the United States made similar efforts. Describing the Formosa [Taiwan] Resolution passed by the U.S. Congress in 1955, Schelling observed that the resolution "was a ceremony to leave the Chinese and the Russians under no doubt that we [the United States] could not back down from the defense of Formosa without intolerable loss of prestige, reputation, and leadership." He added, "We were not merely communicating an intention or obligation we already had, but actually enhancing the obligation in the process."54
113. Arms and Influence appeared, Robert Pape built on Schelling's framework in his book Bombing to Win. He articulated and analyzed four types of coercion that could be carried out by airpower: punishment, denial, risk, and decapitation.56 The first two were clearly familiar to readers of Schelling. Pape's risk category, however, has not generally been adopted in the literature because it is not sufficiently distinguished from punishment.57
114. Focusing on leadership as a center of gravity within an enemy state, decapitation seeks to disrupt an enemy's will and ability to fight by attacking the state's leader and communication assets.58 It rests on the idea that many warlike states are run by authoritarians - individuals who have highly personalized forms of governance that may be subjected to direct assault. Decapitation, which rose to prominence in the era of precision bombing, informed parts of the coercive air campaign over Iraq in the 1991 Gulf War.
115. In general, Pape's work found that punishment, risk, and decapitation all have problems as methods of aerial coercion. Leaders attached to a particular stake are often willing to pass the pain on to their populations in order to protect the survival of the regime. In many instances, local coercive measures - i.e., acts taken on the ground by secret police or other privileged militia groups, such as the SS in World War II - may overwhelm the effects of more remote aerial coercion. Culture and tradition, as in the case of Japan during World War II, may dissuade a population from rising against its leadership, thus thwarting the effects of even overwhelming air strikes.59 Pape found that airpower is most effective as an instrument of denial, working to undermine an adversary's ability to attain military aims.60
116. In land campaigns, ground forces rely on air forces to win and maintain enough control over air space to enable the land battle to be carried on successfully. Since World War I, no industrial nation has been able to fight a peer competitor successfully without the ability to largely control its own airspace and contest enemy airspace. Today, combat forces (of the ground, air, and sea) must also rely on cyber warriors to protect the many systems that enable communication, intelligence, navigation, kinetic action, and situational awareness. Likewise, they rely on space-based assets to enable and facilitate their functioning.61 Securing these systems - which poses an array of new and difficult challenges - has become a high priority for all states that conceive of themselves as major players in the international system. Because of this, these systems - as assets to be protected - now figure, in increasingly important ways, in discussions about deterrence in particular.
117. A coercer, when setting out to influence another actor, must have a strategy for escalation in case its initial efforts fail. It must feel confident that it possesses what theorists call "escalation dominance." Daniel Byman and Matthew Waxman have explained this as, "the ability to increase the threatened costs to the adversary while denying the adversary the opportunity to negate those costs or to counterescalate." They add, "it is through the parties' perceptions that the coercer can achieve the escalation dominance that enables coercive strategies to succeed ... it requires a preponderance that is relevant to every form of possible escalation: no matter where the adversary chooses to increase pressure, the coercer is always able to overwhelm the adversary in that area."62
118. Most practitioners think of nuclear weapons as the pinnacle of the escalatory ladder, and this is certainly true. But coercers possessing nuclear weapons must also have maximum escalatory range in the conventional realm. This is because the stakes in a contest may be very important, but perhaps not important enough for the coercer to credibly contemplate the use of nuclear weapons. If an actor wishes to have dominance in conventional escalation, he must possess land power. The ability of ground armies to land on enemy soil, defeat the adversary's forces (with the aid of air and naval power) and bodily remove the existing leadership - i.e., the threat of brute force/forcible action - provides a coercive tool that is without parallel in the conventional realm. Byman and Waxman explain, "The possible use of ground forces is a potent threat and, if credible, reinforces other instruments by highlighting the potential for escalation."63 Regarding the role of land power in the 1999 Operation Allied Force in Kosovo, they argue that "the threat of NATO ground forces - though ambiguous - helped convince [Slobodan] Milosevic to meet NATO demands over Kosovo."64
119. ne plus ultra when it comes to coercion that is below the nuclear threshold.65 It can confer upon an actor the freedom to depart from the constraints and complications of coercion and move into the realm of brute force/forcible action, where the actor takes what he wants without seeking the adversary's cooperation. This is what Brig. Gen. Huba Wass de Czege meant when he wrote of "vigorous campaigns to force conditions on the enemy regardless of his will."66
120. An army is a powerful, indeed indispensable, tool in the tool box of a major power. Although neither coercion nor brute force is ever a silver bullet, when other coercive leverage has failed, the threat of a land invasion - even a vague threat - is sometimes enough to convince an adversary that the game is no longer worth the candle. And if a state with a powerful army (and sufficient resources to sustain it over time) is simply determined to win a stake, regardless of cost, it has the option to shift to brute force/forcible action. Thus, any state that wants to protect and preserve global interests must possess, and be prepared to use, sophisticated forms of expeditionary land power.67
121. jus post bellum), including postwar political security and stability; and for the care and feeding of the domestic population until a new, functioning structure can be set up. This is an immense task, and an unavoidably expensive one. If an army is used simply to enforce negotiated settlement terms, its responsibilities will be lighter, but they will be significant nonetheless.68
122. For all these reasons, an actor contemplating the use of land power must be prepared to commit to the possibility of a campaign that lasts years (or decades) rather than days and months.69 An adversary state will know all this, and will work hard to determine if a threat of land power is being made genuinely and credibly. Thus, those who would deploy armies must face up to the risks involved in doing so, and must be ruthlessly realistic about the demands and costs of such an undertaking.
123. Persuading decision-makers to fully consider these risks and make crucial calculations can be difficult, however. Political decision-makers generally seek to avoid acknowledging the potential costs of a land campaign - especially the complications of terminating a war and the requirements for transforming what was won by armies into durable and sustainable political gains.70 Politicians will avoid realistic cost estimates because they fear that domestic populations will not want to hear them.71 Meanwhile, military planners will gravitate to the operational details of opening and sustaining campaigns involving land power - they will not be drawn, whether due to natural interest or organizational culture, to the less immediate and perhaps less appealing details of the post-hostilities phases of war. And they may not want to acknowledge fully the asymmetric means and methods that might be employed by an enemy.
124. and civilian decision-makers since, in democracies, both are responsible for strategy.72
125. jus post bellum. If civilian communication with the military is poor, partial, or adversarial - or if civilians sidestep crucial issues of cost and commitment - strategy will suffer. Indeed, these problems can lead to the failure of a campaign or a war.73
126. As it emerges from the long wars that dominated the first two decades of the 21st century, the United States is thinking again about the possibilities of conflict with near-peer competitors and nuclear states. In both realms, coercion theory has a great deal to offer.74 Richard Betts, for instance, has argued the case for using carefully crafted deterrent threats to prevent Iran from using nuclear weapons against third parties. He argues for specific, tailored deterrence. A broad nuclear retaliatory threat (against the Iranian population) might not be believed, but a more specific threat focused on the regime itself - a threat the United States is perfectly capable of carrying out - might well deter Iran from using nuclear weapons in the future.75
127. Betts urges clarity when making deterrent threats. He insists that, as a people and a nation, America ought to determine where its real interests are located, and then bolster them with credible threats to potential trespassers. Citing the example of Korea prior to 1950, and of Iraq in 1990, he observes that when America has communicated its interests and deterrent threats in vague language subject to misinterpretation, it has suffered for it. America should avoid ambiguity, mixed signals, and potential confusion - but he worries that this is precisely the situation in which the United States has placed itself recently regarding Taiwan.76
128. defensive action. Both statesmen and military professionals must fully understand the implications of the "security dilemma": Any steps the United States takes to bolster its own defense will be interpreted by an adversary as offensive or provocative, or both.77 This requires the United States, as it undergirds its defenses, to also communicate its intentions and offer reassurance to limit escalatory tendencies and arms races.
129. National security professionals also need to understand the ways in which military tools may be used in crisis scenarios. Many military instruments are versatile: They can be used to send strong signals that are not inherently escalatory. A good case in point was the use of naval ships to "quarantine" Cuba against the placement of further nuclear weapons in 1962. This line in the sand (or water) drawn by the U.S. Navy was a very clear signal, but was not inherently escalatory. It gave the Soviets the opportunity to withdraw without further inflaming the situation. No doubt it produced a tense and fraught scenario: The Soviets, if they chose not to challenge the U.S. ships, could not escape without some degree of humiliation. But the situation was not nearly so escalatory and unpredictable as an air strike on Cuban soil would have been.78
130. In a similar way, the Berlin airlift of 1948-49 outflanked the Soviet isolation of West Berlin, which lay within the post-World War II Soviet occupation zone, without automatically escalating the situation. The United States, Britain, and France held fast to their commitment to the occupants of the western zones of the city, using a mechanism that was innovative and ultimately effective. In both the Cuba and Berlin cases, the situation did not escalate automatically as a result of U.S. actions. The Soviets themselves would have had to take the responsibility for upping the ante further.79 In neither case, happily, were they willing to do so. Creative thinking, including nontraditional uses of military instruments, proved to be just what the situation required.