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