International Security

This is a guest post from James Igoe Walsh, a political science professor at UNC-Charlotte.

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America’s wars are increasingly fought by drones, not soldiers. Drones reduce the costs of conflict to the United States by eliminating the possibility of American military casualties. Does this make political leaders and the American public more willing to support the use of force? Peter Singer, whose work has done much to highlight the political implications of new military technologies, writes that

The strongest appeal of unmanned systems is that we don’t have to send someone’s son or daughter into harm’s way. But when politicians can avoid the political consequences of the condolence letter — and the impact that military casualties have on voters and on the news media — they no longer treat the previously weighty matters of war and peace the same way.

Drones are indeed popular across the political spectrum. The campaign of drone strikes initiated by the Bush administration in Pakistan has been expanded by the Obama administration to other parts of the world. One recent survey found that eighty-three percent of Americans approve or strongly approve of drone strikes “against terrorist suspects overseas”.

This support for drone strikes is consistent with the large body of research, drawing on John Mueller’s seminal book, which finds an inverse relationship between military casualties and support for the use of force. If such casualty aversion reduces support for the use of force, then drone technology creates a politically easy way to strike overseas. This has disturbing implications. American authorities might authorize strikes against targets that represent little threat to the United States. The United States might resort to drone strikes use them even when their chance of eliminating the target is slight, since there is no downside in terms of US casualties. And it might become increasingly easy to justify drone strikes that will kill (foreign) civilians along with targeted enemies.

But other factors might influence support for drone strikes as well. In Paying the Human Costs of War, Gelpi, Feaver, and Reifler hold that Americans’ support for the use of force depends on their estimates that the military mission will be successful. If perceptions of success are important, Americans might be less willing to support drone strikes that are likely to fail. It is also possible that Americans would decline to support drone strikes that produce civilian casualties, although this proposition has not been as thoroughly investigated in the academic literature.

How well do each of these explanations—casualty aversion, success, and civilian casualties—account for Americans willingness to support drone strikes? The available public opinion data asks respondents only if they support the use of drones, and thus provides little leverage on the question of why they do so. To tackle this problem, earlier this summer I recruited via the internet a convenience panel of 1248 respondents in the United States to participate in a survey experiment. Each respondent was randomly assigned to read a hypothetical news story about planned military strikes on terrorist training camps in Yemen. These vignettes contained different information about the consequences of such strikes. The baseline treatment described the attacks as drone strikes causing no US military casualties, having a high likelihood of military success, and creating no civilian deaths. The next three treatments varied one of these factors, describing the attack as a raid that would produce about 25 US military casualties, as a drone strike that was unlikely to succeed, or a drone strike that would kill civilians. Respondents were then asked to rate their degree of support for this use of force on a four-point scale, with higher values indicating greater support.

The figure below depicts the mean level of support for each of the four treatments, as well as the associated 95 percent confidence intervals. The baseline condition receives the highest level of support. This is not surprising, since it imposes no costs in terms of US or foreign casualties and results in a successful military mission. The remaining treatments all lead to statistically-significant reductions in support compared to this baseline. The smallest such reduction is introduced when the mission is described as unlikely to succeed. Perceptions of success do moderate support for the use of force. However, the fact that this effect is small suggests considerable willingness among some members of the public to risk using deadly force even when it has a high chance of failing.

The treatment describing military casualties leads to a lower level of mean support for the use of force. The chance to avoid military casualties by using drones rather than soldiers produces a noticeable increase in willingness to use force, consistent with the arguments of Mueller and Singer. Finally, the possibility of civilian casualties leads to the largest drop in mean support compared to be baseline treatment. This is a real surprise, since it means that respondents attach as much or more value on the lives of foreign civilians as they do on US military personnel.

It would be unwise to assume that these findings directly reflect the preferences of the American public, since they survey is not based on a random sample. It is, though, reasonable to conclude that the effects of varying the information provided to respondents here would produce qualitatively similar effects in a more representative sample. It is also possible that these relationships would be quite different if what Bruce Jentleson terms the “principal policy objective” where altered from drone strikes to counter terrorists to using drones to, for example, punish abusers of human rights or to bring about regime change overseas.

These results suggest that drones may well alter how Americans think about using military force. The effect of military casualties found here implies that drone technology could make it much easier, and perhaps tempting, for Presidents to use them in conflicts overseas. The smaller effect of mission success means that even the prospect of failure may serve as only a small brake on such impulses. Civilian deaths, though, may well moderate support for drone strikes.