From 2005 to 2016, members of the Australian special forces killed 39 Afghan noncombatants — killings perpetrated not in the “fog of war” but against defenseless civilians and detainees. That’s the key finding from a 531-page report released in November by the Australian Defence Force (ADF), an inquiry that has rattled not only Australia but also human rights advocates and onlookers around the world.

The four-year probe provides new insights into unsettling accusations about actions by ADF special forces members, including allegations of the gruesome murders of two 14-year-old boys, and reports that civilians — including teenagers — were blindfolded, tortured and had their throats slit. The report raises urgent questions about how ADF units could disregard fundamental ethical and legal norms respecting human life.

Collectively, we’ve researched military conduct and combatant attitudes toward “norms of restraint” in diverse contexts, including Australia and the United States. While it’s worth stressing that the Australian and U.S. militaries broadly adopt the tenets of international humanitarian law, here’s what the research suggests about why violations still occur — and what militaries can do to bolster compliance.

Unit subcultures can challenge official rules and norms

International humanitarian law, known also as the law of armed conflict, is the body of law and custom that regulates the conduct of war. It protects persons who are not participating in hostilities and restricts methods of warfare. These principles often form the substantive content for the “norms of restraint” embraced by a nation’s armed forces.

The principle of noncombatant immunity lies at the heart of humanitarian law, forming a cornerstone for the organizational culture of many, if not most, Western militaries. This includes the Australian and U.S. militaries, which historically have had a strong tradition of placing ethics and deference to international law at the center of their activities both on and off the battlefield.

Yet despite this broad embrace of humanitarian law, professional militaries have committed atrocities in Vietnam, Somalia, Iraq and elsewhere. These incidents demonstrate how subcultures emerging in smaller, subordinate units can — if left unchecked — subvert official norms promoting civilian protection.

Close-knit front-line combat units — which often develop unique customs, rituals and identities — are at high risk of fostering unofficial subcultures that challenge official rules and norms. Because of their elite, more insular status, as well as the fact that commanders often grant them greater independence, special operations forces can be especially susceptible to developing toxic unit subcultures that violate official rules and norms. These factors may put special operations forces at greater risk of violating humanitarian law.

The ADF report offers a window into the dangers of these unit subcultures. Among other disturbing allegations, for example, one reputed common practice among Australian special forces was “blooding.” In this type of initiation ritual, patrol commanders ordered junior soldiers to secure their “first kill” by murdering detainees, the report found.

As the ADF investigation makes clear, the interaction between diminished oversight and unofficial subcultures can sow conditions for the dismissal (or even outright rejection) of official regulations, including those designed to promote adherence to the laws of war.

Cultural biases can exacerbate toxic unit subcultures

An expansive literature shows that “opportunisticviolence against civilians is more likely when combatants view civilians as a part of a despised “out-group.” This is particularly salient when fighting occurs in Muslim-majority countries, given the prejudices against this group in much of the West.

Anti-Muslim attitudes appear to be prevalent within elements of the Australian special forces community. One of us, for instance, carried out survey experiments with an Australian special forces unit in 2017, finding nearly unanimous agreement with the statement that “the Muslim religion promotes violence and terrorism.”

News organizations have reported several anti-Muslim episodes not included in the investigation. These include an unearthed video of ADF service members in 2011 demeaning Afghan populations with racist epithets, and a private ADF social media page in 2012 calling Muslims “ragheads.”

Anti-Muslim biases, combined with unofficial unit subcultures and diminished command oversight, may have made compliance with official military rules and norms less likely.

Here’s the research on reducing violence against noncombatants

A key finding from recent research is that compliance with international humanitarian law requires not just simple instruction but also socialization — changing combatants’ internal beliefs on appropriate conduct in war.

This involves a combination of intensive training, exercises, enforcement, military doctrine and other mechanisms to align combatants’ attitudes with official norms, override toxic unit subcultures and reduce out-group biases.

However, new research by one of us suggests that intensive socialization focused specifically on the noncommissioned officers (NCOs) who directly supervise junior soldiers could be particularly effective. Here’s why: Socialization within the military involves a “paradox of rank”— the junior NCOs who hold the greatest influence in shaping the attitudes of the lowest-ranking front-line enlisted soldiers are themselves more resistant to adopting norms of restraint.

Of course, leadership is vital to such socialization. Study after study suggest that the promotion of norms of restraint by the military's top commanders is essential in shaping how soldiers conduct themselves.

It’s important to underscore that the ADF, as an institution, already makes extensive efforts to emphasize ethics and the law of war. Indeed, the overwhelming majority of Australian service members have served with honor in Afghanistan, and ADF regular forces appear to have adhered to international law throughout deployments to Iraq, East Timor and the Solomon Islands.

Despite this, commanders can take steps to rectify deficiencies in socialization processes, improve accountability and reinforce efforts to uphold core rules across units. Australian commanders, for example, authorized an International Committee of the Red Cross study of law and ethics training in the army (which one of us helped lead), revealing a rare degree of openness that has significantly enhanced scholars’ understanding of combatant socialization and restraint.

The ADF investigation, along with the publication of the report’s findings, signal a commitment to transparency over defensiveness. Such transparency is a step — but only the first step — for the ADF, the U.S. military and other armed forces seeking to achieve restraint toward civilians on the battlefield.

Andrew M. Bell (@AndrewBellUS) is an assistant professor of international studies at the Hamilton Lugar School of Global and International Studies at Indiana University and a nonresident fellow at the Modern War Institute at the U.S. Military Academy.

Thomas Gift (@TGiftiv) is an associate professor of political science and director of the Centre on US Politics (@CUSP_ucl) at University College London.

Charles Miller is a lecturer in strategic studies at the Australian National University.