C O R P O R A T I O N MICHAEL J. MAZARR, JOE CHERAVITCH, JEFFREY W. HORNUNG, STEPHANIE PEZARD What Deters and Why Applying a Framework to Assess Deterrence of Gray Zone Aggression For more information on this publication, visit www.rand.org/t/RR3142 Library of Congress Cataloging-in-Publication Data is available for this publication. ISBN: 978-1-9774-0397-1 Published by the RAND Corporation, Santa Monica, Calif. © 2021 RAND Corporation R® is a registered trademark. Cover: REUTERS/Kyodo 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. Permission is given to duplicate this document for personal use only, as long as it is unaltered and complete. Permission is required from RAND to reproduce, or reuse in another form, any of its research documents for commercial use. For information on reprint and linking permissions, please visit www.rand.org/pubs/permissions. The RAND Corporation is a research organization that develops solutions to public policy challenges to help make communities throughout the world safer and more secure, healthier and more prosperous. RAND is nonprofit, nonpartisan, and committed to the public interest. RAND’s publications do not necessarily reflect the opinions of its research clients and sponsors. 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 entitled What Deters and Why: North Korea and Russia, sponsored by the Office of the Deputy Chief of Staff, G-3/5/7, U.S. Army. The purposes of the project were (1) to provide the Army with improved and new frameworks for evaluating the deterrence of aggressor activities for both interstate aggression and aggression short of that threshold and (2) to apply those two frameworks to assess the United States’ conventional and nonconven- tional deterrence relationships with Russia and North Korea. In the latter case, for com- parative purposes, the authors also examine U.S. efforts to deter Chinese aggression. The research and writing for this report were completed in mid-2019. Events and developments since that time are not captured in this narrative. However, although some facts may have changed or new circumstances developed, we believe that the general interpretations, findings, and recommendations remain valid. 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 United States 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 U.S. Department of Defense (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 Contents Preface ................................................................................................. iii Figures and Tables ...................................................................................vii Summary .............................................................................................. ix Acknowledgments .................................................................................. xix Abbreviations ........................................................................................ xxi CHAPTER ONE A Framework for Evaluating Gray Zone Deterrence ........................................... 1 Criteria for Effective Deterrence ..................................................................... 6 Eight Characteristics of Gray Zone Aggression .................................................... 9 Eight Criteria for Deterring High-End Gray Zone Aggression ..................................14 CHAPTER TWO Deterring China’s Gray Zone Aggression Against the Senkaku Islands ..................17 Applying the Framework to China’s Gray Zone Aggression .....................................19 Assessment .............................................................................................49 CHAPTER THREE Deterring Russia’s Gray Zone Aggression Against the Baltic States .......................53 Applying the Framework to Russia’s Gray Zone Aggression .....................................55 Assessment ............................................................................................ 68 CHAPTER FOUR Deterring North Korea’s Gray Zone Aggression Against South Korea ....................73 Applying the Framework to North Korea’s Gray Zone Aggression ............................ 77 Assessment .............................................................................................85 CHAPTER FIVE Conclusions and Implications for the U.S. Army ..............................................89 v vi What Deters and Why: Applying a Framework to Assess Deterrence of Gray Zone Aggression APPENDIX South Korea’s Policy of Disproportionate Retaliation ........................................93 References ........................................................................................... 103 Figures and Tables Figures 1.1. Typology of Conflict ..................................................................... 2 2.1. Senkaku Islands ..........................................................................18 2.2. Chinese Government Vessels Near the Senkaku Islands ........................... 24 5.1. Army Capabilities for Gray Zone Deterrence ........................................91 Tables S.1. Assessment of High-End Gray Zone Deterrence: Chinese Aggression Against the Senkaku Islands ........................................................... xi S.2. Assessment of High-End Gray Zone Deterrence: Russian Aggression Against the Baltic States ...............................................................xiii S.3. Assessment of High-End Gray Zone Deterrence: North Korean Aggression Against South Korea ...................................................... xvi 1.1. Categories of Gray Zone Aggression ................................................... 3 1.2. Potential Future High-End Gray Zone Actions ....................................... 5 1.3. Variables Governing Extended Deterrence of Territorial Aggression ............... 8 1.4. The Gray Zone Challenge to Effective Deterrence ..................................12 1.5. Eight Criteria for Deterring High-End Gray Zone Aggression ....................16 2.1. Chinese Provocations in the South China Sea ...................................... 26 2.2. Assessment of High-End Gray Zone Deterrence: Chinese Aggression Against the Senkaku Islands .......................................................... 50 3.1. Assessment of High-End Gray Zone Deterrence: Russian Aggression Against the Baltic States ................................................................69 4.1. Assessment of High-End Gray Zone Deterrence: North Korean Aggression Against South Korea ...................................................... 86 vii Summary The research reported here was completed in July 2019, followed by security review by the sponsor and the Office of the Chief of Public Affairs, with final sign-off in March 2021. The challenge of deterring major conventional aggression is taking on renewed impor- tance in an era of strategic competition. But the nature of that competition, which is primarily playing out below the threshold of major war (at least so far), has created a more immediate and persistent challenge for deterrence: the rise of gray zone aggres- sion, as opposed to conventional interstate aggression. We define gray zone aggression as an integrated campaign to achieve political objectives while remaining below the threshold of outright warfare. Typically, such campaigns involve the gradual applica- tion of instruments of power to achieve incremental progress without triggering a deci- sive military response.1 To help establish how to deter gray zone aggression, we first identified its unique characteristics. Eight distinctive characteristics of gray zone activities are as follows: 1. falls below the threshold for military response 2. unfolds gradually 3. is not attributable 4. uses legal and political justifications 5. threatens only secondary national interests 6. has state sponsorship 7. uses mostly nonmilitary tools 8. exploits weaknesses and vulnerabilities in targeted countries and societies. In addition, we developed a framework for assessing the health of deterrence in the gray zone. Because many low-end (less-aggressive) gray zone activities cannot be deterred, we identified criteria for deterring high-end (more-aggressive) gray zone activities. Eight general categories of criteria for deterring high-end gray zone aggres- sion are as follows: 1. intensity of the aggressor’s motivations 2. attribution of the aggressor’s role 1 The research and writing for this report were completed in mid-2019. Events and developments since that time