

A rally outside the White House in May 2011 after news broke that Osama bin Laden had been killed. (Matt McClain/For The Washington Post)

The botched execution two weeks ago of an Oklahoma death-row inmate has reinvigorated the debate over capital punishment. And though the death penalty fight is multifaceted, much of the disagreement boils down to retribution: Does justice require that a person who commits the ultimate crime be punished in kind?

New research by two political scientists suggests that the desire for this kind of retributive justice, or vengeance, can also explain Americans’ foreign policy attitudes. People who adopt an “eye for an eye” mentality are more likely to support military force, the torture of terrorism suspects and the use of drone strikes. Retribution isn’t just about the criminal justice system.

In one paper, Peter Liberman measured survey respondents’ levels of retribution by asking how strongly they agreed or disagreed with the statement that “those who hurt others deserve to be hurt in return.”

People were then randomly assigned into two groups. One group was asked whether they would support the use of American military force in various scenarios —for instance, if a North Korean submarine attacked a U.S. Navy warship. A second group was given the same hypothetical situations but also was told that the attacks had resulted in fatalities. This allowed Liberman to determine whether a desire for retribution was a stronger predictor of opinion if the aggressive action had resulted in deaths.

That’s exactly what he found. A respondent’s desire for retribution had no effect on support for U.S. military action when fatalities weren’t mentioned. But when they were, support increased as a respondent’s level of retribution did.

In a separate analysis, Liberman also found that, controlling for other factors, people high in retribution were more likely to approve the torture of terrorists. The results suggest that support for torture may not only stem from a belief that it can lead to valuable intelligence. Some people may also simply believe that waterboarding is what terrorists deserve.

A second paper, by my colleague Rachel Stein, finds that a desire for vengeance also explains support for overseas drone strikes.

Stein conducted an experiment in which subjects were told that a drone attack was to be carried out against a terrorist leader responsible for a deadly assault on a U.S. military base. One group learned that the leader’s home was in “a remote location so that no innocent civilians will be killed.” A second group was told the home was in “a densely populated location so it is very likely that innocent civilians will be killed.”

Stein found two things. First, a desire for revenge — how strongly people agreed with the statement that “in order for justice to be served, violence must be repaid with violence” — increased support for the drone strike.

Second, the prospect of civilian casualties reduced support by about 42 points among people on the lower end of the vengefulness scale. But among people who “somewhat” or “strongly” agreed that violence should be repaid in kind, civilian casualties lowered support by just 11 points, a difference that was not statistically significant.

(It’s worth noting that in other experimental manipulations, Stein found no evidence that telling respondents that a foreign government had given the United States permission to conduct the mission or that the terrorist was American-born had any effect of on support, regardless of levels of vengefulness.)

The findings underscore a challenge for opponents of drone strikes who have sought to call attention to civilian casualties. “For a substantial portion of the population,” Stein writes, “the righteousness of punishing evildoers creates a psychological buffer that allows them to maintain support for drone strikes without the cognitive dissonance and self-censure that might otherwise come with endorsing a policy that results in the death of innocent people.”

Ultimately, Americans’ foreign policy attitudes are the product of a variety of considerations, including messages from elites, underlying political values and beliefs, and maybe even the challenges of geography. But Liberman and Stein’s work suggests that the moral roots of national security opinion can’t be ignored.