Rethinking the “Reasonable Prospect of Success” Principle in Just War Doctrine

Abstract

A “reasonable prospect of success” (RPS) is commonly listed among the criteria that state leaders must follow when resorting to war. However Just War Doctrine scholars have undertheorized the criterion, resulting in two dominant stances in the extant literature: one camp rejects the principle as a normative requirement, while the other replaces “success” from “victory” to some other goal, like honor. We argue both approaches are misguided and ignore the crucial question of who has the authority to decide when RPS is acceptable. We offer a novel four-pronged framework for assessing RPS. What constitutes legitimate “success” in a particular war? How probable must that success be to qualify as “reasonable?” Are leaders being “reasonable” in the manner of their decision-making? Who has the authority to decide these questions? We argue that the answers to these questions are deeply intertwined and that all must be met for RPS to be meaningfully satisfied. We illustrate the value of this framework through new interpretations of the Melian resistance to Athen’s assault on their city-state in 416 BC and the Ukrainian resistance to Russia’s invasion in 2022, arguing that the former may not have been a just resistance because the oligarchs did not permit democratic deliberation, while the latter was just as the Ukrainian people supported resistance.

Biography

Scott D. Sagan is Co-Director and Senior Fellow at the Center for International Security and Cooperation, the Caroline S.G. Munro Professor of Political Science, and the Bass University Fellow in Undergraduate Education at Stanford University. He also serves as Co-Chair of the American Academy of Arts and Sciences’ Committee on International Security Studies. Before joining the Stanford faculty, Sagan was a lecturer in the Department of Government at Harvard University and served as special assistant to the director of the Organization of the Joint Chiefs of Staff in the Pentagon.

Sagan is the author of Moving Targets: Nuclear Strategy and National Security (Princeton University Press, 1989); The Limits of Safety: Organizations, Accidents, and Nuclear Weapons (Princeton University Press, 1993); and, with co-author Kenneth N. Waltz, The Spread of Nuclear Weapons: An Enduring Debate (W.W. Norton, 2012). He is the co-editor of Insider Threats (Cornell University Press, 2017) with Matthew Bunn; and co-editor of The Fragile Balance of Terror (Cornell University Press, 2022) with Vipin Narang. Sagan was also the guest editor of a two-volume special issue of Daedalus: Ethics, Technology, and War (Fall 2016) and The Changing Rules of War (Winter 2017).

Recent publications include “Kettles of Hawks: Public Opinion on the Nuclear Taboo and Noncombatant Immunity in the United States, United Kingdom, France, and Israel”, with Janina Dill and Benjamin A. Valentino in Security Studies (February 2022); “The Rule of Law and the Role of Strategy in U.S. Nuclear Doctrine” with Allen S. Weiner in International Security (Spring 2021); “Does the Noncombatant Immunity Norm Have Stopping Power?” with Benjamin A. Valentino in International Security (Fall 2020); and “Just War and Unjust Soldiers: American Public Opinion on the Moral Equality of Combatants” and “On Reciprocity, Revenge, and Replication: A Rejoinder to Walzer, McMahan, and Keohane” with Benjamin A. Valentino in Ethics & International Affairs (Winter 2019).

In 2022, Sagan was awarded Thérèse Delpech Memorial Award from the Carnegie Endowment for International Peace at their International Nuclear Policy Conference. In 2017, he received the International Studies Association’s Susan Strange Award which recognizes the scholar whose “singular intellect, assertiveness, and insight most challenge conventional wisdom and intellectual and organizational complacency" in the international studies community. Sagan was also the recipient of the National Academy of Sciences William and Katherine Estes Award in 2015, for his work addressing the risks of nuclear weapons and the causes of nuclear proliferation. The award, which is granted triennially, recognizes “research in any field of cognitive or behavioral science that advances understanding of issues relating to the risk of nuclear war.” In 2013, Sagan received the International Studies Association's International Security Studies Section Distinguished Scholar Award. He has also won four teaching awards: Stanford’s 1998-99 Dean’s Award for Distinguished Teaching; Stanford's 1996 Hoagland Prize for Undergraduate Teaching; the International Studies Association’s 2008 Innovative Teaching Award; and the Monterey Institute for International Studies’ Nonproliferation Education Award in 2009.

Rhiannon Neilsen is the Assistant Professor in International Security at the Marxe School of Public & International Affairs, Baruch College, City University of New York (CUNY).

Her research sits at the intersection of international security (specifically conflict), new technologies, and ethics. She also draw on moral and political philosophy to consider the case for deploying disinformation and deception to parry atrocity crimes. Her first book, Algorithms & Atrocities, is under contract with Oxford University Press (Bridging the Gap series). It introduces the concept of 'cyber humanitarian interventions' to prevent genocides, war crimes, crimes against humanity, and ethnic cleansing.

Most recently, she was the Cyber Security Postdoctoral Fellow in the Center for International Security and Cooperation (CISAC) at Stanford University.