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Do U.S. Military Interventions Occur in Clusters?

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Research brief

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When Department of Defense DoD force planners use planning constructs and deployment scenarios to estimate force requirements, they assume that U.S. military interventions occur independently of each other, meaning that the likelihood of each deployment is unaffected by the timing or frequency of past deployments. However, U.S. experiences in Southeast Asia during the 1960s, the Balkans during the 1990s, and the Middle East since 2001 suggest that military interventions may not be independent but may instead exhibit temporal dependence that is, one intervention may increase the likelihood of subsequent interventions in the near future. If true, interventions would be more likely to occur in clusters. A clustered pattern of interventions would result in different demands for U.S. military capabilities than those current DoD approaches to force planning produce. This report assessed whether there is empirical evidence of temporal dependence in U.S. Army interventions and, similarly, whether armed conflicts themselves exhibit the same pattern. The author analyzed 66 cases of U.S. Army interventions from 1949 to 2010, defining intervention as an Army deployment of company size or larger for contingency and peacekeeping or peace enforcement operations, thus excluding air strikes, airlift, humanitarian operations, sea- and air-based noncombatant evacuations, and small deployments of U.S. military advisers and trainers. The analysis tested for a dependent relationship between military interventions in one period and those before it and incorporated intervening factors that might affect the likelihood of military interventions and intervention clusters. These factors include underlying domestic political characteristics U.S. presidential popularity, economic trends U.S. gross domestic product and unemployment, and strategic contexts relative U.S. power, level of international conflict, and the collapse of the Soviet Union.

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  • Humanities and History
  • Military Operations, Strategy and Tactics

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