Using a game theoretic approach, Phil Haun sets out to explain: a) why it is that in asymmetric conflicts, weak states so often resist coercion by strong states; and b) why the United States, in particular, persists in resorting to coercion despite its frequent failure. Haun focuses on the United States because since World War II, it has employed coercion against weaker states more frequently than any other major power—23 cases between 1950 and 2011. In twelve of these cases, coercion failed to elicit the concessions demanded, and in eight, Washington finally gave up on its demands rather than go to war.

By “coercion,” Haun means threats and the limited use of force for demonstration purposes, as distinct from “coercive diplomacy” (threats short of the actual use of force), and “brute force” (war). An asymmetric relationship is one in which a strong state can threaten the existence of a weak state, but the weak state cannot threaten the existence of the strong. In asymmetric conflict, one would expect the United States to frequently opt for coercion rather than brute force because the costs are lower and the U.S. interests at stake are usually not vital. Moreover, the asymmetry of power should induce the weak state to concede in the face of coercion rather than risk a war it cannot win.

So why don't weak states concede more often? Haun concludes that the U.S. power advantage is so great that it tends to demand too much, insisting on concessions that would put the very existence of the target state at risk—territorial losses, regime change, or concessions so unpopular at home that they might provoke internal revolt. As C. Fred Bergsten put it, talking about the limited efficacy of economic sanctions, you cannot expect a regime to “commit political suicide” (Council on Foreign Relations. 1998. “Sanctions Against Rogue States: Do They Work?” May 20). From a game theory perspective, concessions that threaten a weak state's survival are no more preferred than war. On the contrary, if a weak state can manage to resist coercive demands, there is at least a chance that the strong state will back down rather than incur the cost of resorting to brute force. Since the stakes for the weak state are so high, it has greater resolve than the strong state, for whom the stakes are usually modest.

This logic has been explored in studies of economic sanctions, but Haun chooses not to engage that literature, arguing that his focus is on the threat of violence rather than economic harm. This distinction seems artificial; economic sanctions and military sanctions (violence) both cause harm to the target country, which would presumably be willing to pay some price to avoid it. There is no obvious reason that the logic of the game should be any different in the case of military sanctions than economic ones.

We know from Gary Clyde Hufbauer, Jeffrey J. Schott, Kimberly Ann Elliott, and Barbara Oegg (2009. Economic Sanctions Reconsidered. Washington, DC: Peterson Institute for International Economics) that economic sanctions are most likely to be effective when they are multilateral, comprehensive, target a regime that is economically vulnerable, and have a modest, limited goal. Haun's argument would be stronger if he linked it explicitly to what we know about economic sanctions, especially since his theory appears to be consistent with that literature—especially regarding the kinds of demands made of the weak state.

Why does Washington so often make demands that the target state is likely to resist? Theoretically, Haun argues, the United States should use coercion only to make demands that the small state is willing to accept; to ask more is to court failure leading to war or require backing down, with its associated reputational costs. Yet more often than not, Washington asks too much.

One reason for making unrealistic demands is to intentionally elicit rejection, thereby creating a casus belli for war. As Haun points out, the international community expects strong states to try to resolve disputes diplomatically before resorting to force, so even an insincere attempt at coercive diplomacy has value in paving the road to war. In his case study of the U.S. invasion of Iraq, Haun argues that George W. Bush never intended to resolve the conflict short of war. Even when Saddam Hussein agreed to U.S. demands for weapons inspection on the eve of the U.S. invasion, Washington would not take yes for an answer. But such cases are the exception. Most of the time, when coercion fails, Washington simply gives up or settles for less.

Haun never offers a clear explanation for why the United States repeatedly makes this mistake. He surveys the literature of rationalist and nonrational causes of war, but finds them all wanting in one way or another. He would do well to give greater attention to nonrational factors such as emotion, and rationalist factors such as imperfect information and domestic political constraints. Emotions can distort judgments, color interpretations of facts, and magnify perceptions of the stakes. Imperfect information—which is always a problem in international crises (call it the fog of diplomacy)—can easily lead to miscalculations. Finally, as Robert Putnam argues (1988. “Diplomacy and Domestic Politics: The Logic of Two-Level Games.” International Organization 42: 427–460), domestic political calculations are as important as international ones in foreign policy decision-making. Decision-makers play a “two-level game,” looking for a solution set that satisfies both their international aims and their domestic constituents. Haun takes the domestic sphere into account when explaining a weak state's resolve to resist; it is equally important for understanding a strong state's choice of demands.

After laying out his theory of coercion in asymmetric relationships, Haun examines seven cases studies to demonstrate the theory's applicability: the Gulf War; the invasion of Iraq; the Bosnian civil war; the 1998 crisis in Kosovo; the U.S. bombing of Libya in 1986 over its support for terrorism; the Libyan bombing of Pam Am flight 103; and Libya's agreement to end development of weapons of mass destruction. Strictly speaking, the bombing of flight 103 is not a case of coercion because the U.S. responded with economic sanctions rather than the threat of force, but Haun notes that it fits the theory nevertheless—which reinforces the suspicion that the distinction he draws between economic and military sanctions is an artificial one.

On the whole, Haun's theory fits his cases reasonably well, though some creative interpretation is required when the facts don't quite fall neatly into line—especially in the complex cases of Bosnia and Kosovo. In Kosovo, Haun acknowledges, Slobodan Milosevic gave up territory that he regarded as part of the Serbian homeland, which the theory predicts he should not have done short of all out war.

Using case studies to empirically test game theoretic models of international relations is tricky: One can observe what the actors do and how they respond to one another's moves. But knowing what they are thinking—whether they are making the sort of rational calculations the theory postulates—is quite a high hurdle to clear, especially since their deliberations are almost always secret. This dilemma creates a temptation to engage in some deductive mind-reading: If country A behaves the way the theory predicts, it must be because leader A made the rational calculations the theory requires.

Haun recognizes this danger and is explicit in admitting that we do not know what Muammar Qaddafi was thinking most of the time, so the analysis of the Libyan cases is based on “how Qaddafi likely perceived the fact presented to him” (p. 137). We have somewhat better documentation of how other leaders saw things, but the other cases do not entirely escape the temptation to read into the thinking of the decision-makers the rational calculations that fit the theory.

Nevertheless, Haun has given us a valuable contribution to understanding the dynamics of asymmetrical power relationships in the international system and why conflicts between strong and weak states sometimes teeter precariously at the threshold between coercion and war.