Hybrid Threats in the Grey Zone

December 5 -
 7, 2019

Co-sponsored By:

The Conference

This workshop-style conference is the second in a two-part series addressing the legal and moral complexities of what is commonly referred to as “Grey Zone Conflict.” The first conference was held in Charlottesville, Virginia and hosted by The Judge Advocate General’s Legal Center and School (TJALCS.)

The  United States Special Operations Command defines this zone as “a conceptual space between peace and war, occurring when actors purposefully use single or multiple elements of power to achieve political-security objectives with activities that are typically ambiguous or cloud attribution and exceed the threshold of ordinary competition, yet intentionally fall below the level of large-scale direct military conflict.”

While such forms of competition have always occurred, advances in communications and information technology amplify their potential effect, and make possible the simultaneous use of multiple tactics in coordinated campaigns.  Such campaigns may result in sudden acquisition of advantage, or they may be gradual and long-term, seeking incremental changes to avoid provocation whose cumulative effect may be to change balances of power.

These operations pose particular challenges because they typically fall between legally accepted forms of competition and legally prohibited armed attacks.  The resulting ambiguity creates instability in the international arena because states are uncertain about behavior that will be considered acceptable and responses that will be regarded as justified.  The absence of clear legal guidance reflects a deeper failure to determine ethical norms that should govern activity in the grey zone. 

This workshop brings together thinkers from various disciplines to map the terrain characterized by hybrid threats in the grey zone. This will involve discussion of the specific types of threats and the issues that they raise, how these threats may be connected to one another, the responses that may be effective in response to them, and the potential for legal and ethical principles to provide greater clarity and structure about what is and is not acceptable behavior.   

This conference is by invitation only and closed to the public. 


Thursday, December 5


5:00 PM to 6:30 PM
Penn Law – Fitts Auditorium
3501 Sansom Street – Lower Level

Reception to follow

Friday, December 6 

8:30 am – 9:30 amRegistration and Continental Breakfast
9:30 am – 9:45 amWelcoming Remarks by Claire Finkelstein, Mitt Regan and Aurel Sari
9:45 am – 11:00 amSession 1: Conceptual FoundationsModerator: Claire FinkelsteinThe Grey Zone and Hybrid Conflict: A Conceptual Introduction
Christopher MarshWe Have Met the Grey Zone and It is Us
Duncan MacIntoshThe Divide between War and Peace
Tobias Vestner
11:00 am – 11:30 amBreak 
11:30 am – 12:45 pmSession 2: Making Sense of the Grey ZoneModerator: Michael AdamsThe Grey Zone: An Analytic Framework for Military Overt, Covert, and Paramilitary Lines of Effort
Maegen Nix & Welton ChangMeasured Self-Help in the Disinformation Age
Steven J. Barela & Samuli HaatajaNon-Intervention 2020
Ido Kilovaty
12:45 pm – 2:00 pmLunch – The White Dog Café – The Living Room.
2:00 pm – 3:15 pmSession 3: Tactics in the Grey Zone (1)Moderator: Aurel Sari

Neuroscience and Technology in Grey Zone Operations
James GiordanoThe Ethics of Acting Covertly
Mitt ReganLying in the Grey Zone
Steven Wheatley
3:15 pm – 3:45 pmBreak 
3:45 pm – 5:30 pmSession 4: Tactics in the Grey Zone (2)Moderator: Todd HuntleyEconomic Measures in the Grey Zone
Mitchell OrensteinLawfare
Orde KittrieCounter-Lawfare: The Israeli Experience
Marlene Mazel
5:45 pm – 7:00 pmReception (Levy Conference Center at Penn Law)
7:00 pm – 9:00 pmParticipants’ Dinner and Keynote (Levy Conference Center at Penn Law)Deak Roh, Director of Irregular Warfare
US Department of Defense

Saturday, December 7

8:00 am – 9:00 amRegistration and Continental Breakfast
9:00 am – 10:30 amSession 5: DomainsModerator: Christopher JacobsInformation Operations
Beba CibralicThe Maritime Domain
David LettsHybrid Warfare in Outer Space
Melissa de Zwart & Dale Stephens 
10:30 am – 10:45 amBreak 
10:45 am – 12:15 pmSession 6: ResponsesModerator: Mitt ReganAn Ethical Framework for Assessing Grey Zone Responses
Ed BarrettWinning at the Seams
Michael A. NewtonCompeting in the Legal Domain: Legal Operations
Borja Montes ToscanoLegal Resilience
Aurel Sari
12:15 pm – 12:30 pmConcluding remarks: Aurel Sari & Mitt Regan


CDR (ret) Mike Adams

 Executive, Palantir Technologies

Professor Edward Barrett

Stockdale Center for Professional Leadership, US Naval Academy

Ms. Beba Cibralic

Doctoral Student, Doctor of Philosophy, Georgetown University

Ms. Arlene Fickler 

Partner, Schnader Harrison Segal & Lewis LLP; CERL Executive Board Member 

Professor Claire Finkelstein

CERL Founder & Faculty Director; Algernon Biddle Professor of Law and Professor of Philosophy, University of Pennsylvania 

Professor James Giordano

Chief of the Neuroethics Studies Program, Scholar-in-Residence, leads the Sub-Program in Military Medical Ethics, and Co-director of the O’Neill-Pellegrino Program in Brain Science and Global Health Law and Policy in the Pellegrino Center for Clinical Bioethics

Capt. (ret) Todd Huntley 

National Security Law Program Director and Lecturer in Law, Georgetown University Law Center 

LTC (Ret.) Christopher Jacob 

Senior Fellow, CERL, University of Pennsylvania Carey Law School

Professor Ido Kilovaty 

Frederic Dorwart Endowed Assistant Professor of Law, University of Tulsa School of Law

Professor Duncan Macintosh

 Chair, Philosophy Department, Dalhousie University, CERL Executive Board Member

Ms. Marlene Mazel

Director, Counter-Terrorism & Foreign Litigation Division, Israeli Ministry of Justice

CTR Borja Motes Toscano

LAWFAS Content Manager, ACO Office of Legal Affairs 

Professor Michael Newton

 Professor of the Practice of Law,Professor of the Practice of Political Science, Director, Vanderbilt-in-Venice Program, Vanderbilt University Law School

Dr. Maegan Nix 

Applied Physics Laboratory, Johns Hopkins University   

Professor Mitchell Orenstein 

Professor of Russian and East European Studies, University of Pennsylvania

Professor Mitt Regan

McDevitt Professor of Jurisprudence, Director of the Center on Ethics and the Legal Profession, and Co-Director on the Center on National Security and the Law at Georgetown University Law Center

Mr. Deak Roh

 Director, Irregular Warfare and Partnerships at Office, Secretary of Defense

Dr. Aurel Sari

Senior Lecturer, Director of Exeter Centre for International Law

Mr. Tobias Vestner

Head of Security and Law, Geneva Centre for Security Policy 

Mr. Christopher Welsh

 CERL Executive Director 

Mr. Paul Welsh

 Vice President of Business Development, Analytical Graphics, Inc.; CERL Executive Board Member 

Professor Steven Wheatley 

Professor of International Law, University of Lancaster

Mr. Jules Zacher 

Attorney at Law; CERL Executive Board Member 

Background Readings


George F. Kinnan, Policy Planning Staff Memorandum (1948)

Todd C. Huntley and Andrew Levitz, Controlling the Use of Power in the Shadows: Challenges in the Application of Jus in Bello to Clandestine and Unconventional War Activities, Harvard National Security Journal, Vol. 5 (2014)

Catherine Lotrionte, Reconsidering the Consequences for State-Sponsored Hostile Cyber Operations Under International Law, 3 The Cyber Defense Review 73 (2018) 

Michael N. Schmidt, Virtual Disenfranchisement: Cyber Election Meddling in the Grey Zones of International Law, 19 Chicago Journal of International Law 30 (2018)

Michael Waltzer, Soft War: The Ethics of Unarmed Conflict, Cambridge University Press, Foreword (2017) 

Lt/ Douglas Cantwell, Hybrid Warfare: Aggression and Coercion in the Gray Zone, ASIL Insights, Vol. 21, Issue 19 (2017)

Mary Ellen O’Connell, Cyber Security without Cyber War, Journal of Conflict & Security Law, Vol. 17 No. 2, 187-209  (2012)

Michael N. Schmitt, Grey Zones in the International Law of Cyberspace, Yale Journal of International Law Online (2017) 

George R. Lucas, Jr., State Sponsored Hacktivism and the Rise of ‘Soft’ War, Soft War: The Ethics of Unarmed Conflict, Cambridge University Press (2017)

Oona A. Hathaway, Rebecca Crootof, Philip Levitz, Haley Nix, Aileen Nowlan, William Perdue & Julia Spiegel, The Law of Cyber-Attack, 100 Calif. L. Rev. 817 (2012)

Barrie Sander; Democracy Under The Influence: Paradigms of State Responsibility for Cyber Influence Operations on Elections, Chinese Journal of International Law (2019)

Claire Finkelstein, Book Review, Michael L. Gross and Tamar Meisels (eds). Soft war: the ethics of unarmed conflict. Cambridge University Press (2017)

Derek Jinks, State Responsibility for the Acts of Private Armed Groups, 4 Chicago Journal of International Law (2003)

C. Anthony Pfaff, Proxy War Ethics, Journal of National Security Law and Policy, Vol 9:305 (2017) 

Luca Ferro & Nele Verlinden, Neutrality During Armed Conflicts: A Coherent Approach to Third-State Support for Warring Parties, 17 Chinese Journal of International Law 15 (2018)

Gloria Gaggioli, Targeting Individuals Belonging to an Armed Group, 51 Vanderbilt Journal of Transnational Law 901 (2018)

Rory Cormac & Richard J. Aldrich, Grey is the New Black: Covert Action and Implausible Deniability, 94 International Affairs 477 (2018)

David Carment et al., Gray zone mediation in the Ukraine crisis: comparing Crimea and Donbas (forthcoming 2019)

A. V. Demin, Soft Law Concept in a Globalized World: Issues and Prospects, Law Journal of the Higher School of Economics 49 (2018)

Andrew Mumford, Proxy Warfare and the Future of Conflict, The RUSI Journal (2013)

James Pattison, The Ethics of Arming Rebels, Ethics & International Affairs 29, no. 4 (2015)

Michael Jefferson Adams, Jus Extra Bellum: Reconstructing the Ordinary, Realistic Conditions of Peace Harvard National Security Journal (2014)  

Mihail Naydenov, Building the Capacity Of NATO’S Eastern European Members to Fight Hybrid War, 41 Information & Security 45 (2018)

Roger McDermott, Does Russia Have a Gerasimov Doctrine, Parameters 46, no. 1 (Spring 2016)  

Claire Finkelstein and Kevin Govern, Introduction: Cyber and the Changing Face of War (2015)

Sean Watts, Low-Intensity Cyber Operations and the Principle of Non-Intervention (May 5, 2014)

Michael L. Gross and Tamar Meisels (eds). Soft war: the ethics of unarmed conflict. Cambridge University Press (2017)

Robert R. Greene Sands, Language and Culture Note #1: On the Gray Zone and the Space Between War and Peace, Small Wars Journal 


Aurel Sari, Legal Aspects of Hybrid Warfare, Lawfare blog post (October 2, 2015) 

General Joseph T. Votel et al., Unconventional Warfare in the Gray Zone, NDU Press (July 2016)

Neither War Nor Peace: The uses of constructive ambiguity. The Economist (January 25, 2018)

David Daoud, Meet the Proxies: How Iran Spreads is Empire through Terrorist Militias. The Tower (March 2015)

Daniel L. Byman, Why Engage in Proxy War? A State’s Perspective, Lawfare (2008)

Laurence Peter, Syria War: Who Are Russia’s Shadowy Wagner Mercenaries?, BBC News (February 2018)  

Rosa Brooks, Rule of Law in the Gray Zone, Modern War Institute (July 2, 2018)  

Nicholas Heras, Gray Zones in the Middle East, CNAS (September 18, 2017)

Frank Hoffman, On Not-So-New-Warfare: Political Warfare vs. Hybrid Threats, War on the Rocks (July 2014)

Michael Kofman, Russian Hybrid Warfare and Other Dark Arts, War on the Rocks (March 2016)

Ofek Riemer and Daniel Sobel, Coercive Disclosure: Israel’s Weaponization of Intelligence, War on the Rocks (August 30, 2019)

Philip Kapusta, The Gray Zone, Special Warfare Magazine (October – December 2015)

Contact us

For any questions regarding the conference or registration, please contact: Jennifer Cohen at

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