Moral Obligations and Military Intervention

Blog | September 26, 2017

Moral obligation plays an important and overlooked role in U.S. public attitudes towards military action.


In his speech outlining U.S. policy towards Afghanistan, Donald Trump assured the public that he shared their frustration with a foreign policy that did not pursue U.S. “security interests over all other considerations.” This laser-focus on achieving U.S. security at all costs echoes realists from Thucydides to Thomas Hobbes to George Kennan, who have long represented the conventional wisdom when it comes to the way that states should or do interact with other states. From this view, political reality must be intertwined with power and self-interest—morality is simply a sideshow against this theoretical backdrop.

Trump’s ends-justify-the-means rhetoric and concern with public opinion date back to campaign promises that his policy towards the use of torture would depend on whether “Americans feel strongly about bringing back waterboarding and other tactics.” But, is President Trump right to assume the public shares his frustration with a foreign policy focused on anything other than the narrowly defined promotion of U.S. security interests? Our research, published in the Journal of Conflict Resolution, suggests the opposite is the case. Moral obligation plays an important and overlooked role in U.S. public attitudes towards military action.

In this research, we recruited a national sample of U.S. adults to participate in a survey experiment that examined whether support for humanitarian interventions is grounded in moral concerns about protecting foreign civilians or more instrumental, national interest-focused concerns about costs and consequences. In the post-Cold War period, half of the United States’ military interventions have taken the form of humanitarian interventions, the use of force across borders for the primary purpose of saving foreign civilians. The 1990s were the heyday of U.S.-led humanitarian interventions, referred to by critics as a foreign policy of “social work.” Examples from this period include the Somalia intervention in 1992-1993, Bosnia in 1995, and Kosovo in 1999. However, more recent interventions in Libya and Syria also carried humanitarian overtones, suggesting that the practice is alive and well in this decade.

Findings show that these humanitarian overtones actually increased public support for humanitarian intervention scenarios compared to “realpolitik”-style operations such as restraining an aggressive state. However, higher levels of support for these interventions derived not from the assumptions about costs in blood and treasure that shape responses to security interventions but from moral motives. Faced with the prospect of a humanitarian crisis, individuals were drawn to support military action out of a sense of moral obligation and belief that the US and its allies “ought” to intervene on behalf of foreign civilians.

Today, in an increasingly polarized political context where partisanship pervades every aspect of public life, a follow-up analysis was conducted to investigate whether individuals’ party identification plays a role in the types of interventions they support and why. Results drawn from our 2015-2016 study indicate that Republicans offer high and consistent levels of support for all forms of military intervention and the prospect of humanitarian motives does little to boost their support for the use of force—in other words, there is a ceiling effect that makes additional upward movement more difficult. Republicans also felt a sense of moral responsibility for intervention of all kinds, whether humanitarian or ejecting an authoritarian leader who invaded another country. On the other hand, Democrats were more leery of the use of force in response to foreign aggression but were animated by the prospect of humanitarian motives because they were concerned about harm done to foreign civilians and felt a sense of moral obligation for U.S. action. While the content of their moral concerns varied, across the board moral considerations loom large for both Republicans and Democrats.

Our research has focused primarily on attitudes of Americans because the United States has tended to assume a dominant international role when it comes to the use of force. Previous studies suggest, however, that other democratic publics, especially the United Kingdom, often converge with American attitudes when it comes to support for military force, suggesting that these attitudes likely travel to other democratic populaces as well.

Several years ago, the political scientist John Mearsheimer reported that “realism is a hard sell.” Realist compatriot Henry Kissinger similarly lamented that “Americans cannot sustain major international obligations that are not justified by their moral faith.” Despite efforts aimed at offering a more self-serving perspective of the public, our research indicates that the realist lament largely rests on firm ground. Americans are not simply moved to expend resources for self-interest or for violations of state sovereignty. They value the prospect of saving strangers in distant lands, and do so exactly on the basis of moral faith. Leaders who dismiss these moral mechanisms undermine not only the international legitimacy of military action, but their own domestic basis of support.


Sarah Kreps is an associate professor of government and adjunct professor of law at Cornell University. Sarah Maxey is a postdoctoral fellow at Perry World House at the University of Pennsylvania. This article outlines the findings of a recent article in the Journal of Conflict Resolution.  


The views expressed in this post reflect those of the author and not that of the EastWest Institute.