What Deters and Why Exploring Requirements for Effective Deterrence of Interstate Aggression Michael J. Mazarr, Arthur Chan, Alyssa Demus, Bryan Frederick, Alireza Nader, Stephanie Pezard, Julia A. Thompson, Elina Treyger C O R P O R A T I O N For more information on this publication, visit www.rand.org/t/RR2451 Library of Congress Cataloging-in-Publication Data is available for this publication. ISBN: 978-1-9774-0064-2 Published by the RAND Corporation, Santa Monica, Calif. © Copyright 2018 RAND Corporation R® is a registered trademark. Cover: Three ROK soldiers watching the border at Panmunjeom in the DMZ between North and South Korea/Henrik Ishihara via Wikimedia Commons (CC BY-SA 3.0) Limited Print and Electronic Distribution Rights This document and trademark(s) contained herein are protected by law. This representation of RAND intellectual property is provided for noncommercial use only. Unauthorized posting of this publication online is prohibited. 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Support RAND Make a tax-deductible charitable contribution at www.rand.org/giving/contribute www.rand.org Preface This report documents research and analysis conducted as part of a project enti- tled What Deters and Why: Lessons of Deterrence Theory and Practice for U.S. Army Forces and Capabilities, sponsored by the Office of the Deputy Chief of Staff, G-3/5/7, U.S. Army. The purpose of the project was to provide the U.S. Army with an analysis of fundamental deterrence theory and its potential applications to challenges of interstate aggression, including a specific case study of deterring Russian aggression in Europe. The Project Unique Identification Code (PUIC) for the project that produced this document is HQD177483. This research was conducted within RAND Arroyo Center’s Strategy, Doctrine, and Resources Program. RAND Arroyo Center, part of the RAND Corporation, is a federally funded research and development center (FFRDC) sponsored by the U.S. Army. RAND operates under a “Federal-Wide Assurance” (FWA00003425) and com- plies with the Code of Federal Regulations for the Protection of Human Subjects Under United States Law (45 CFR 46), also known as the Common Rule, as well as with the implementation guidance set forth in DoD Instruction 3216.02. As applicable, this compliance includes reviews and approvals by RAND’s Institutional Review Board (the Human Subjects Protection Committee) and by the U.S. Army. The views of sources utilized in this study are solely their own and do not represent the official policy or position of DoD or the U.S. Government. iii RR2451A_CC2015.indb 3 7/19/18 4:50 PM RR2451A_CC2015.indb 4 7/19/18 4:50 PM Contents Preface ................................................................................................. iii Figures .................................................................................................vii Tables .................................................................................................. ix Summary .............................................................................................. xi Acknowledgments ................................................................................. xvii Abbreviations ........................................................................................ xix CHAPTER ONE Understanding Deterrence and Dissuasion ...................................................... 1 Defining Deterrence and Dissuasion ................................................................ 2 A Comprehensive Approach to Preventing Aggression: Strategies of Dissuasion .............. 6 Key Distinctions ....................................................................................... 7 Intentions, Rationality, and Perception .............................................................10 The Choice to Initiate Aggression: Messy, Gradual, and Emergent .............................13 CHAPTER TWO Effective Deterrence and Dissuasion: A Framework for Analysis ..........................15 Challenges in Determining What Prevents Aggression ..........................................16 Category One: How Intensely Motivated Is the Aggressor? .....................................17 Category Two: Is the Defender Clear and Explicit Regarding What It Seeks to Prevent and What Actions It Will Take in Response? ...................................... 22 Category Three: Does the Potential Aggressor View the Defender’s Threats as Credible and Intimidating? .................................................................... 23 Summary and Proposed Framework for Deterrence Effectiveness ............................. 34 CHAPTER THREE Evaluating and Revising the Framework: Quantitative and Case Study Assessments ......................................................................................37 Quantitative Assessment of U.S. Extended Deterrence Cases Since 1945 .....................37 Qualitative Assessment: In-Depth Extended Deterrence Case Studies .........................39 A Revised Framework of Factors Associated with Deterrence Success .........................53 v RR2451A_CC2015.indb 5 7/19/18 4:50 PM vi What Deters and Why CHAPTER FOUR Applying the Revised Framework: Deterring Russia in the Baltic Region ...............55 How Motivated Is Russia? ...........................................................................57 How Clear and Explicit Is the U.S. Deterrent Message? .........................................63 Is the U.S. Deterrent Message Credible and Convincing? .......................................70 Conclusion .............................................................................................79 CHAPTER FIVE Conclusions, Recommendations, and Implications for the U.S. Army ................... 87 Recommendations ....................................................................................89 Implications for the U.S. Army ..................................................................... 92 APPENDIXES A. Quantitative Analysis: Cases of U.S. Extended Deterrence Since 1945 ...............93 B. Qualitative Case Study Analyses: Berlin .................................................. 109 C. Qualitative Case Study Analyses: Deterring Saddam, 1990 .......................... 131 D. Qualitative Case Study Analyses: NATO’s Northern Flank in the Cold War ..... 145 E. Qualitative Case Study Analyses: Russian Aggression Against Georgia............ 165 Bibliography ........................................................................................ 189 -1— 0— +1— RR2451A_CC2015.indb 6 7/19/18 4:50 PM Figures 1.1. Deterrence and Dissuasion .............................................................. 7 A.1. Regional Distribution of Deterrence Success in the Face of a Highly Motivated Aggressor ......................................................... 103 C.1. Timeline of Events in 1990 Leading Up to the Iraqi Invasion of Kuwait ....... 133 D.1. The GIUK Gap and the Strategic Situation of the Northern Flank ............. 147 D.2. U.S. Military Personnel Permanently Stationed in Northern Europe, 1950–1992 .............................................................................. 148 D.3. The Position of Kolsås and Murmansk Relative to Finnmark .................... 150 E.1. Map of Georgia ........................................................................ 166 vii RR2451A_CC2015.indb 7 7/19/18 4:50 PM RR2451A_CC2015.indb 8 7/19/18 4:50 PM Tables 2.1. Literature Review: Initial Set of Key Variables .......................................35 3.1. Key Variables ............................................................................ 54 4.1. Application of the Deterrence Framework to Russia in the Baltic States ........ 80 4.2. Recommendations for U.S. Deterrent Posture in the Baltics ...................... 84 5.1. Conclusions: Key Variables Governing the Success of Deterrence................ 88 A.1. All Cases ..................................................................................95 A.2. Cases of Failed Deterrence ............................................................. 96 A.3. Cases of Successful Deterrence ........................................................ 97 A.4. Deterrence Success in the Face of a Highly Motivated Aggressor ............... 100 A.5. Deterrence Success with Limited or Ambiguous Clarity ......................... 104 A.6. Deterrence Success Where There Was U.S. Disadvantage in the Local Balance of Forces ............................................................... 106 A.7. Quantitative Analysis: Confirmed Variables ....................................... 107 C.1. Application of the Framework to the Iraq Case .................................... 144 D.1. Application of the Framework to the Case of the United States Deterring the USSR .................................................................. 162 E.1. Application of the Framework