"In recent years, the frequency of U.S. military interventions in overseas areas, including not only those involving conventional war but also peacekeeping and humanitarian relief operations, has risen. These interventions have involved thousands of troops, cost billions of dollars, and placed significant demands on Army leadership, planning, and resources. The Army would benefit from an enhanced ability to anticipate the types and conditions of overseas military interventions it is most likely to be called upon to undertake in the future. This report constructs three different sets of models using historical data (one for each of three intervention types: interventions into armed conflict, stability operations in conflict and postconflict environments, and deterrent interventions). It examines the key factors influencing the incidence of military interventions and intervention size. Finally, the analysis provides the Army with signposts and metrics that can be used to identify countries, conflicts, and crises that are at highest risk for a U.S. intervention. Key signposts include the relationship between the target of the intervention and the United States, past U.S. military involvement in that country, and the severity of the crisis or threat to which the United States is responding. These signposts would allow the Army to better anticipate and plan for future interventions and could improve both near- and medium-term force-planning decisions"--Publisher's description.

"October 12, 2017"--Table of contents page.

Preface --Figures -- Tables -- Summary -- Acknowledgments -- Abbreviations -- 1. Introduction: -- Study Approach -- Organization of This Report -- 2. Historical Analysis of U.S. Army Interventions: -- RUGID: -- Variables in the Intervention Data -- Variables in the Unit Type Data -- Historical Trends in U.S. Ground Interventions: -- Trends in Activity Types -- Trends in Location -- Trends in Duration and Size -- Analysis of Unit Types in U.S. Ground Interventions: -- Trends in Unit Type Use -- Relationship Between Unit Type and Activity -- Relationship Between Unit Type and Intervention Size -- Unit Type Mismatches and Shortages -- Summary: Which Units Are Most Stressed? -- Has the United States Intervened in the Past?: -- Interventions into Armed Conflict -- Stability Operations -- Deterrent Interventions -- Implications -- Summary and Implications -- 3. Determinants of the Likelihood and Size of Interventions: -- Existing Literature and Its Shortcomings: -- Characteristics of the International Environment -- Characteristics of the Conflict or Crisis -- Domestic Characteristics of the United States -- Characteristics of the Target State -- Characteristics of the Relationship Between the Target State and the United States: -- U.S. Interests -- Limitations of Existing Research -- Identifying Determinants of the Likelihood and Size of Ground Interventions: -- Methodology: An Overview -- Interventions into Armed Conflicts -- Interventions to Conduct Stability Operations -- Interventions to Increase Deterrence -- Summary and Implications -- 4. Clustering: -- What Is Intervention Clustering? -- A Look at the Data -- Why Would Interventions Cluster? A Review of Existing Literature -- Mechanisms of Intervention Clustering -- Approach -- Results -- Summary and Implications -- 5. Why Use Case Studies? Purpose and Methodology: -- Case Study Insights and Takeaways: -- Lead Time, Duration, and Withdrawal -- Resource Demands and Constraints -- Leading Indicators and Warning Signs of Future Interventions -- Summary and Implications -- Ties to Statistical Analysis -- 6. Signposts of Future Interventions: -- Defining a Signpost -- Signposts for Interventions into Armed Conflict: -- Relationship with the United States -- Destructiveness of the War -- Previous Intervention -- War Weariness -- U.S. Capabilities -- Attack on U.S. Soil -- Public and Elite Opinion -- Signposts of Stability Operations Interventions: -- Location of the Target -- Number of Refugees -- Involvement in the Combat Phase -- Military Assistance -- Wealth of Target Nation -- Multinational Coalition -- Signposts of Deterrent Interventions: -- Degree of Threat -- Relationship with the United States -- Military Assistance -- Rate of U.S. Economic Growth -- Signposts for Clustering: -- Recent Interventions in Target Country -- Recent Interventions in Proximate Countries -- Summary and Implications -- 7. Implications for Army Planners: -- Signposts of Future Interventions -- Signposts and Potential Future Interventions -- Other Key Insights for Army Planners -- Directions for Future Work -- APPENDIXES: -- A. RUGID Codebook and Methodology -- B. Case Studies -- C. Trends in Unit Type Use -- D. Statistical Appendix -- References.