Explaining Changes in U.S. Grand Strategy : 9/11, the Rise of Offensive Liberalism, and the War in Iraq

This paper proposes a model for explaining shifts and variations in US grand strategy. The model is based on a distinction between four ideal-type grand strategies or approaches to security according to the objectives and means of security policy: defensive and offensive realism, and defensive and offensive liberalism. While the four approaches are continually present in the US policy community, it is the combination of two systemic conditions, namely the distribution of capabilities and the balance of threat, that selects among the competing approaches and determines which grand strategy is likely to emerge as dominant in a given period. While great power parity is conducive to realist approaches, a situation of hegemony allows the liberal perspectives to emerge. In addition, a relative absence of external threat encourages defensive approaches, while a situation of high external threat gives rise to offensive strategies. Thus, various combinations of these systemic factors give rise to the emergence of various grand strategies. This model is tested in two cases of the two most recent shifts in US grand strategy following 1991. In accordance with the expectations of the model, a change in the distribution of capabilities with the end of Cold War made possible a change from realist to liberal strategies. In the benign environment of the 1990s the dominant strategy was defensive liberalism, while the change in the balance of threat after 9/11 gave rise to the grand strategy of offensive liberalism