Political ideology shapes views on acceptable civilian casualties in war

Across different types of military conflicts, people who hold conservative political views are more willing to accept unintended civilian deaths than people with liberal views. This ideological divide remains consistent whether the war features real adversaries, strategic partners, or entirely fictional nations. The findings were recently published in the European Journal of Social Psychology.

Public opinion plays a major role in how governments wage war and handle international conflicts. Tolerance for civilian casualties can influence diplomacy, military strategy, and humanitarian aid. Researchers wanted to understand what drives the deep political divisions often seen in public polling about wartime casualties. They questioned whether this divide was tied to specific real-world conflicts or if it reflected a deeper psychological difference between political groups.

The research team was led by Julia Elad-Strenger, a researcher at Bar-Ilan University in Israel. She worked alongside Daniel Statman from the University of Haifa and Thomas Kessler from Friedrich Schiller University Jena in Germany. They designed a series of experimental surveys to isolate the moral dimensions of wartime decision-making. Specifically, they wanted to see if right-leaning individuals generally tolerate more civilian deaths than left-leaning individuals across varied situations.

The researchers designed the study to solve a specific problem found in previous polling data. Past surveys often blurred the lines between whether a war itself is justified and whether specific actions within that war are justified. By setting all their scenarios strictly as wars of self-defense, the team held the initial justification for war constant. This isolated the participants’ views entirely on the actions taken during the combat itself.

To explain why these differences might exist, the team looked at a psychological framework known as moral foundations theory. This theory suggests that human morality is built on a few basic pillars. Some are considered individualizing foundations, which focus heavily on protecting individuals from harm and ensuring absolute fairness across the board. Others are known as binding foundations, which emphasize maintaining group loyalty, prioritizing respect for authority, and protecting social purity.

The researchers conducted six separate studies involving thousands of participants from Israel and the United States. In most of the experiments, participants read a short text describing a war of self-defense. In the story, one nation is attacked and prepares to strike the enemy’s military headquarters, which is located in a populated civilian area. To isolate pure ethical judgments from practical military realities, the team also measured how many casualties participants thought were strictly unavoidable to achieve the military goal.

After reading the scenarios, participants were asked to state the absolute maximum number of unintended civilian deaths they would consider morally acceptable. To ensure their results were not just tied to single real-world events, the researchers changed the identities of the warring groups across experiments. Israeli participants read scenarios involving actual adversaries like the Palestinians or Iran, as well as a strategic partner like Egypt. American participants were given identical scenarios but featuring North Korea as an active rival and Iraq as a strategic partner.

In other versions of the survey, the researchers used entirely made-up countries to remove any preexisting historical biases. They also changed the perspective of the participants within these fictional scenarios. In some cases, participants were asked to imagine they were a citizen of the country conducting the military strike. In others, they acted as neutral, outside observers watching the conflict unfold. This allowed the researchers to separate basic nationalism from underlying moral judgments.

The results remained remarkably consistent across all the variations. Right-leaning participants regularly reported a much higher acceptable number of civilian casualties than left-leaning participants. This ideological gap appeared when evaluating current enemies, strategic allies, and completely fictional nations. It also persisted whether the participants imagined themselves as members of the attacking nation or as unaffiliated observers.

When investigating the reasons behind this divide, the researchers found that individualizing moral foundations provided the strongest explanation. Left-leaning individuals scored much higher on measures of harm avoidance and fairness. This strong focus on protecting individual welfare regardless of group identity was directly linked to lower acceptance of civilian casualties.

On the other hand, the researchers looked at binding moral foundations, which prioritize group loyalty and security. While right-leaning individuals did score higher on these group-focused values, this difference did not entirely explain their higher tolerance for civilian deaths. The ideological gap was driven primarily by differing levels of concern for individual harm, rather than differing levels of group loyalty.

The researchers also tested whether people were simply following the expected norms of their political parties. While perceived political norms did play a role in some of the hypothetical scenarios, individual moral values remained the strongest and most consistent factor. To test this in reality, the researchers conducted one of their studies during the actual outbreak of the Israel-Hamas war in late 2023. Even in the midst of a real-life crisis with high national solidarity, the difference between left and right persisted, driven again by individualizing moral values rather than group consensus.

In their final experiment, the researchers attempted to manipulate these perceived group norms directly. They showed participants data suggesting that their own political group either strongly opposed or largely accepted civilian casualties. While this successfully changed what participants believed their political peers thought, it did not alter their personal judgments about acceptable casualty levels. This reinforced the idea that deeply held personal values dictate these views.

While the results span multiple contexts, the researchers note a few limitations to their work. The real-world scenarios used in the studies involved foreign rivals that are generally perceived as less democratic than the participants’ own nations. This specific dynamic might increase the perceived justification for military action and shape the results in ways that a conflict between two similar allied democracies would not.

Additionally, asking people to estimate acceptable casualty numbers in hypothetical scenarios might not perfectly capture how they process real-time news about wartime deaths. Exploring how people react to casualties inflicted by an allied country could reveal different psychological patterns. The dynamic could also shift entirely if researchers asked participants about casualties inflicted upon their own nation by a foreign power.

Future studies are needed to see if these patterns hold in countries with lower levels of political polarization. The researchers also suggest looking into longitudinal data to track how these moral judgments might shift over a person’s lifetime. They hope to eventually test whether exposing people to different moral frameworks can temporarily alter their acceptance of civilian harm during times of war.

The study, “Left-Right Ideological Differences in Moral Judgments: The Case of Acceptance of Collateral Civilian Killings in War,” was authored by Julia Elad-Strenger, Daniel Statman, and Thomas Kessler.