Three of the more important international developments of the last half century are the “long peace” between the superpowers, the Soviet Union's renunciation of its empire and leading role as a superpower, and the post-cold war transformation of the international system. Realist theories at the international level address the first and third of these developments, and realist theories at the unit level have made an ex post facto attempt to account for the second. The conceptual and empirical weaknesses of these explanations raise serious problems for existing realist theories. Realists contend that the anarchy of the international system shapes interstate behavior. Postwar international relations indicates that international structure is not determining. Fear of anarchy and its consequences encouraged key international actors to modify their behavior with the avowed goal of changing that structure. The pluralist security community that has developed among the democratic industrial powers is in part the result of this process. This community and the end of the cold war provide evidence that states can escape from the security dilemma.

The author contends that the difference between so-called factual and counterfactual arguments is greatly exaggerated; it is one of degree, not of kind. Both arguments ultimately rest on the quality of their assumptions, the chain of logic linking causes to outcomes, and their consistency with available evidence. He critiques two recent historical works that make extensive use of counterfactuals and finds them seriously deficient in method and argument. He then reviews the criteria for counterfactual experimentation proposed by social scientists who have addressed this problem and finds many of their criteria unrealistic and overly restrictive. The methods of counterfactual experimentation need to be commensurate with the purposes for which it is used. The author discusses three uses for counterfactual arguments and thought experiments and proposes eight criteria appropriate to plausible-world counterfactuals.

Deterrence theories purport to supply the auxiliary assumptions rational choice theories need to predict rational strategic behavior. They generally assume that would-be initiators are (i) instrumentally rational; (2) risk-prone gain-maximizers; (3) free of domestic constraints; and (4) able to identify themselves correctly as defenders or challengers. These assumptions are contradicted by empirical studies that indicate that risk-prone, gain-maximizing initiators are relatively uncommon; that leaders at times calculate as deterrence theories expect, but behave contrary to their predictions; and that the calculus of initiators generally depends on factors other than those identified by deterrence theories. Deductive theories of deterrence are also inadequate because they do not define their scope conditions. Nor can they accommodate deviation by initiators from processes of rational calculation. Rational deterrence theories are poorly specified theories about nonexistent decision makers operating in nonexistent environments.

We report a series of studies of historical reasoning among professional observers of world politics. The correlational studies demonstrate that experts with strong theoretical commitments to a covering law and cognitive-stylistic preferences for explanatory closure are more likely to reject close-call Counterfactual that imply that “already explained” historical outcomes could easily have taken radically different forms. The experimental studies suggest that counterfactual reasoning is not totally theory-driven: Many experts are capable of surprising themselves when encouraged to imagine the implications of particular what-if scenarios. Yet, there is a downside to openness to historical contingency. The more effort experts allocate to exploring counterfactual worlds, the greater is the risk that they will assign too much subjective probability to too many scenarios. We close by defining good judgment as a reflective-equilibrium process of balancing the conflicting causal intuitions primed by complementary factual and counterfactual posings of historical questions.

Part I of this essay reviews cases of deterrence failure and assesses the political, psychological, and practical obstacles to the success of deterrence. The evidence suggests that the utility of deterrence is limited to a narrow range of cases. It is appropriate only when leaders are motivated largely by ' 'opportunity" rather than by "need," have the political freedom to exercise restraint, are not misled by grossly distorted assessments of the political-military situation, and are vulnerable to the kind of threats a deterrer can make. Deterrence must also be practiced early on, before an adversary commits itself to a challenge and becomes correspondingly insensitive to warnings that its action is likely to meet with retaliation. Unless these conditions are met, deterrence will at most be ineffective and at worst counterproductive. Part I1 examines deterrence successes and those cases where deterrence might have succeeded had it been attempted. A case-by-case review makes it apparent that there are few unambiguous examples of the success of deterrence. Inevitably, proponents of deterrence resort to counte$actual reasoning to allege that deterrence would have worked had it been tried. A review of these arguments suggests that they too are frequently open to multiple interpretation. Because the evidence of success is ambiguous and because deterrence can be ineffective, uncertain, and risky, it must be supplemented by other strategies of conflict management. Part III looks beyond deterrence to strategies of "reassurance" that might substitute for or complement deterrence and reduce some of its obvious risks. Strategies of reassurance presume ongoing hostility but, unlike deterrence, root the source of that

Empirical analyses of deterrence have paid insufficient attention to the validity and reliability of the data used to test the central propositions of theories of deterrence. This article examines two prominent studies of immediate extended deterrence that do not deal adequately with the problems inherent in constructing a valid data set for quantitative analysis. The problems are particularly acute in the testing of theories of deterrence because of the difficulties in identifying cases of deterrence success and of inferring the intentions of would-be challengers. Our analysis explores these problems and suggests ways of testing theories of deterrence that can reduce the threats to valid inference.

Identity is the master variable for many constructivist scholars of international politics. In this comparative study, Richard Ned Lebow shows that states do not have identities any more than people do. Leaders, peoples, and foreign actors seek to impose national identifications consistent with their political projects and psychological needs. These identifications are multiple, fluid and rise in importance as a function of priming and context. Leaders are at least as likely to invoke national identifications as rationalizations for policies pursued for other reasons as they are to be influenced by them. National identifications are nevertheless important because they invariably stress the alleged uniqueness of a people and its country, and are a principal means of seeking status and building self-esteem. Lebow tracks the relative appeal of these principles, the ways in which they are constructed, how they influence national identifications, and how they in turn affect regional and international practices.

Drawing on Kant and Hegel, debates in political theory and international relations generally assume that an identity cannot be created without the simultaneous creation and negative stereotypy of an `other'. Figures such as Schmitt and Huntington accept and even welcome this binary, while others, among them Nietzsche, Habermas and Rawls, look for ways of overcoming it. Drawing on Homer's Iliad and psychological research, I challenge the assumptions on which Kant and Hegel, and their successors, build their argument. The Greco-Roman literary tradition and recent survey and experimental research indicates that identities generally form prior to construction of `others', that `others' need not be associated with negative stereotypes, and that even when they are, boundaries between in- and outgroups are quite plastic. Nor must stereotypes be negative. Homer and modern history suggest that identity construction and maintenance often take place through positive, although not necessarily equal, interactions with `others'.