Attitudes toward the Use of Force: Instrumental Imperatives, Moral Principles, and International Law

What informs ordinary citizens’ attitudes toward the use of force? Previous research identifies several key concerns in public opinion toward war, but does not directly evaluate the relative importance of these considerations. We articulate three distinct logics of war support—moral, legal, and instrumental—and use an experimental survey with 3,000 U.S. respondents to test how ordinary citizens make trade-offs among multiple competing imperatives relevant for decision making in war. Our design is the first to isolate to what extent substantive legal demands, instrumental military imperatives, and specific moral principles are reflected in respondents’ preferences. Although all logics have some resonance, we find that respondents’ preferences are remarkably consistent with several core demands of international law even though respondents are not told that the legality of the use of force is at stake. Only the imperative to minimize U.S. military casualties overwhelms both legal and moral demands. Verification Materials: The data, code, and any additional materials required to replicate all analyses in this article are available on the American Journal of Political Science Dataverse within the Harvard Dataverse Network, at: https://doi.org/10.7910/DVN/H8HM6P. I n war, moral principles about the permissibility of killing and instrumental military imperatives often directly contradict each other. International law, meanwhile, makes distinct substantive demands for how force must be used that accommodate instrumental and moral imperatives to some extent, but track neither in full. To what extent do ordinary citizens’ attitudes toward the wartime use of force reflect substantive demands of international law, specific moral principles, or instrumental considerations? We articulate three logics of support for the use of force: an instrumental logic focused on maximizing military effectiveness, a moral logic concerned with minimizing individual rights violations, and a logic that reflects the substantive demands of international law. We evaluate the relative importance of these logics in a study of respondent preferences in the United States, the democratic state to have used force in its international affairs most often in the twenty-first century. Studies have highlighted that public opinion is crucial Janina Dill, John G. Winant Associate Professor of U.S. Foreign Policy, Nuffield College, Department of Politics and International Relations, University of Oxford, Manor Road, Oxford, OX1 3 UQ, United Kingdom (janina.dill@politics.ox.ac.uk). Livia I. Schubiger, Douglas and Ellen Lowey Assistant Professor, Department of Political Science, Duke University, Gross Hall, 140 Science Drive, Durham, NC 27708 (livia.schubiger@duke.edu). We thank Christian Mueller, Gabby Levy, Diego José Romero, and Marta Talevi for excellent research assistance. For helpful comments we thank Jasmine Bhatia, Peter Feaver, Todd Hall, Joshua Kertzer, Sarah Kreps, Thomas Leeper, Kate Millar, Brian Rathbun, Scott Sagan, Sebastian Schutte, Henry Shue, Duncan Snidal, Seiki Tanaka, Geoffrey Wallace, Matthew Zelina, the participants of the LSE Political Behaviour seminar, the Oxford IR colloquium, the Essex Government Department seminar, the Nuffield Political Science colloquium, the Konstanz workshop on the Micro-Dynamics of Political Violence, the LSE Security & Statecraft workshop, the Harvard Law School Program on International Law & Armed Conflict, the Oslo Department of Political Science, the Political Theory Project at Brown University, the TISS seminar, the Political Economy & Political Science workshop in Santiago de Chile, as well as panels at the 2018 Annual Convention of the International Studies Association, the 2018 Annual Midwestern Political Science Association Conference, and the 2018 Annual Meeting of the American Political Science Association. We are grateful for financial support to the LSE Suntory and Toyota International Centre for Economics and Related Disciplines (STICERD) and the LSE Department of International Relations. The preanalysis plan for this study has been archived with EGAP (ID:20170816AA). American Journal of Political Science, Vol. 00, No. 0, xxxx 2021, Pp. 1–22 © 2021 The Authors. American Journal of Political Science published by Wiley Periodicals LLC on behalf of Midwest Political Science Association DOI: 10.1111/ajps.12635 This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.