Soldier Self-Defense Symposium: Individual Self-Defense in Armed Conflict – a US Perspective

[Colonel (retired) Randall Bagwell served 30 years as a legal advisor for the US Army, deploying on numerous operations. He is now the Director of International Humanitarian Law for the American Red Cross. Any views expressed in this paper are his personally, and should in no way be attributed to the US Army or the American Red Cross. This post is part of our week-long symposium on soldier self-defense and international law.]

In the US military, individual self-defense is a muddled concept. US criminal law provides one standard for self-defense, that will be used if a soldier is charged in a criminal court, while the US Standing Rules of Engagement (SROE) provide another standard for self-defense that is not based in criminal law, but rather is a delegation of national self-defense. This article draws on a previous discussion of how the mixing of these two distinct self-defense standards can result in confusion on the part of soldiers and a misapplication of self-defense in armed conflicts.

Criminal Law Self-Defense

Even though it is often referred to as a right, in most US jurisdictions, self-defense is an affirmative defense to a criminal charge of homicide or assault. In practice however, this distinction lacks significance as many people in the US regard criminal self-defense as a recognition of a right of self-defense. Although the requirements for self-defense vary depending on each state’s criminal code, in some form or the other, everyone in the US has a right to use force against a person who wrongfully seeks to cause them immediate death or grievous bodily harm.

In the US military, individual self-defense is recognized in Rule for Courts Martial (RCM) 916(e) – “It is a defense to a homicide, assault involving deadly force, or battery involving deadly force that the accused: (A) Apprehended, on reasonable grounds, that death or grievous bodily harm was about to be inflicted wrongfully on the accused; and (B) Believed that the force the accused used was necessary for protection against death or grievous bodily harm.” The Military Judge’s Benchbook, 5-2-1, interprets the phrase “about to be inflicted” as immediate.

A few important items are worth noting. First, for assaults that do not involve death or grievous bodily harm, self-defense under the RCM is still available, but the force used must be less than force reasonably likely to produce death or grievous bodily harm. Second, the threat of harm must be wrongful. Self-defense is not available when the person threatening death or bodily harm has a legal right to do so. For example, a person has no right to claim self-defense against the lawful use of force by a policeman making an arrest. Third, acting in self-defense of another person is permitted in the same circumstances that would permit self-defense on the part of the individual using force if he were defending himself. For example, a soldier who sees a person being assaulted can defend that person to the same extent that he would be allowed to defend himself if he were the one being attacked. Fourth, in determining whether a sufficient threat was present, the court can consider whether the soldier claiming self-defense had the possibility of safe retreat, although retreat is not required.  Finally, a soldier’s right to claim self-defense, and the requirements to do so, do not change whether the soldier is on duty or off, in or outside the US, or in peace or armed conflict. Put another way, a soldier has the same legal right to claim criminal self-defense, and must meet the same requirements, whether he is walking the streets of Washington, DC or Kandahar, Afghanistan. This point will be further developed in the examples below.

The Defense of Justification

No discussion of US individual self-defense in armed conflict is complete without also discussing RCM 916(c), the defense of justification: “A death, injury, or other act caused or done in the proper performance of a legal duty is justified and not unlawful.” The RCM discussion to this rule specifically cites the example that “killing an enemy combatant in battle is justified.” This is important in the context of self-defense because if a soldier is charged with murder for killing a person in an armed conflict, it is likely that the defense of justification would be more applicable at his trial than self-defense.

There are situations that may arise in armed conflicts where both justification and self-defense could apply as overlapping authorities. One example would be killing a person who was taking direct part in hostilities who was also an immediate threat to cause the soldier death or grievous bodily harm.

However, in most armed conflict situations, such an act would be better categorized as a justified, and therefore lawful action under International Humanitarian Law (IHL), which permits the killing of civilians taking direct part in hostilities. Thus, what is often cited as individual self-defense by US soldiers in armed conflict situations, would be more correctly cited as justification (see below examples under “Why it matters”).

Standing Rules of Engagement Self-Defense

The Standing Rules of Engagement (SROE) are rules dictating how US military forces can use force. Their purpose is to provide commanders with guidance on using force in the event their unit is attacked during peacetime, while also providing optional rules, based in IHL, that allow for a rapid transition to a more robust use of force if an armed conflict begins.

At the heart of the SROE is US self-defense policy, addressing national, unit, collective, and individual self-defense. Despite the use of these different self-defense labels, the SROE are just addressing national self-defense in jus ad bellum. The terms national, unit, collective and individual, are merely designations for when, and by whom, national self-defense can be authorized. Most importantly, individual self-defense as stated in the SROE is not the same as criminal self-defense.

The SROE draw their authority from international law, not criminal law. This is evident from the way the self-defense authorities mentioned in the SROE all nest, like a Russian stacking doll, within the context of jus ad bellum national self-defense. The SROE define national self-defense as “Defense of the United States, US forces, and, in certain circumstances, US persons and their property, and/or US commercial assets from a hostile act or demonstration of hostile intent.” The SROE then nest the concept of unit self-defense under national self-defense. “Unit commanders may exercise National Self-Defense” and “Unit commanders always retain the inherent right and obligation to exercise unit self-defense in response to a hostile act or demonstrated hostile intent.” Collective self-defense, “Defense of designated non-US military forces and/or designated foreign nationals and their property,” is also provided for in the SROE. When authorized, it is also considered an extension of unit, and hence national, self-defense under international law. Then the SROE finally nests the concept of individual self-defense under the concept of unit self-defense. This is not done in the criminal self-defense context, but rather in the context of the individual soldier being the small unit of the US military. “When individuals are assigned and acting as part of a unit, individual self-defense should be considered a subset of unit self-defense. As such, unit commanders may limit individual self-defense by members of their unit.” This last statement, “commanders may limit individual self-defense,” is possible in the SROE because commanders can limit a soldier’s ability to exercise national self-defense. In criminal law self-defense, a commander has no such authority.

The idea that self-defense in the SROE is merely national self-defense exercised by different tiers of actors, is also supported by the use of a common set of definitions for all three levels. Definitions that are different from the definition used for criminal law self-defense. The SROE characterizes a threat triggering self-defense as a hostile act, “an attack or other use of force against the United States, forces or other designated persons or property,” or a demonstration of hostile intent, “the threat of imminent use of force against the United States, US forces or other designated persons or property.” Included as a hostile act or demonstration of hostile intent is the use of force, or threat of force, “to preclude or impede the mission and/or duties of US forces, including the recovery of US personnel or vital USG property.” Applying these definitions to individual self-defense, it is clear that they are vastly broader than how a threat is defined in criminal law self-defense.

Further bolstering the argument that SROE individual self-defense is part of national self-defense is the fact that the SROE explicitly state that the word imminent, used in the context of demonstrated hostile intent, does not necessarily mean immediate or instantaneous. This puts the SROE definition directly at odds with RCM criminal law self-defense, which requires the threat to be immediate. Additionally, the principles of self-defense of de-escalation, necessity and proportionality stated in the SROE are also phrased in a jus ad bellum national self-defense context, rather than RCM criminal defense or jus in bello context. 

Individual self-defense as stated in the SROE is a delegation of national self-defense, therefore the need to invoke this authority should end once a conflict begins. Once the conflict starts, IHL is triggered and as the more specific use of force paradigm, should control. National self-defense is a justification for why states enter armed conflicts, not a legal authority for fighting within one. Problematically though, US soldiers continue to assert SROE self-defense as an authority to use force in armed conflict. This misapplication of SROE self-defense occurs most often because the SROE do not provide authority for US soldiers to use force against individuals who are taking a direct part in hostilities. Absent this authority, soldiers are misapplying SROE self-defense, a jus ad bellum authority, to fill a gap in a jus in bello situation.     

Why it matters

The SROE are policy by which the US delegates to its soldiers the authority to use force on behalf of the nation. They are not law. Rules of engagement (ROE) can restrict authority available to soldiers under the law, but they cannot expand it. If a soldier wants to claim individual self-defense to actions he took in a combat zone, he will be judged in court using the RCM definition, not the SROE definition. 

By using the term individual self-defense, not in its true criminal law meaning, but rather as a policy tool to inform soldiers when they can act independently in exercising national self-defense, the SROE set up a confusing framework for soldiers and commanders. In many situations where a soldier kills a person in armed conflict, it isn’t the RCM on self-defense that comes into play in courts, but rather the RCM on justification. This is because actions, including killing someone, carried out under the legal authority of the State under international law are permissible.

To better understand the difference, let’s examine three scenarios applying both SROE individual self-defense and criminal law self-defense. The first two involve a non-international armed conflict and the man who is shot is wearing civilian clothing. In the third, the man who is shot is a member of the enemy armed forces and is wearing a uniform in an international armed conflict.

In the first scenario, the soldier is charged with murdering a man who he believed was emplacing an improvised explosive device (IED). The soldier stated to investigators he shot the man in self-defense because the man was demonstrating hostile intent by presenting an imminent threat in accordance with the SROE. At his trial for murder, the soldier would be able to raise the defense of justification, but not self-defense. Self-defense in a criminal context is not available because the man’s act of emplacing the IED did not place the soldier in immediate fear of death or serious bodily harm. The defense of justification should apply because the man’s actions in emplacing the IED likely qualify as taking a direct part in hostilities, thereby making him subject to attack under IHL. Although the soldier may claim he acted in self-defense under SROE, this type of self-defense, national self-defense, is not permissible in a criminal trial.

SROE self-defense does not come into play in this situation because there is already an armed conflict, and the concept of national self-defense, a justification for entering into an armed conflict, ends once the conflict has begun. However, by following the standard of SROE self-defense the soldier was actually applying the IHL authority to use force against someone taking a direct part in hostilities. This example highlights a few points. First, that SROE self-defense does not require the act to present an immediate threat, while criminal law self-defense does. Second, when soldiers claim they acted in self-defense in an armed conflict, in most situations they should claim justification as their defense. Third, applying the SROE self-defense standard will often result in the same outcome as applying IHL authority to use force against someone taking a direct part in hostilities, albeit a more restricted version. While that may be a desired outcome under US policy, misapplying SROE self-defense in armed conflict situations unnecessarily places more restrictions on soldiers than direct participation in hostilities authority would.      

In the second scenario, the soldier is charged with murder for shooting a man who raised a rifle and pointed it at the soldier. At the soldier’s murder trial, he can assert both defenses of justification and self-defense. In making the case for justification, he would argue that the man’s actions identified him as a civilian taking a direct part in hostilities and, therefore shooting him was justified under IHL. He could also claim criminal self-defense if he can show that he reasonably believed the man was about to immediately inflict death or grievous bodily harm on him, and that he subjectively believed his use of deadly force in this situation was necessary to prevent this harm. While both defenses are available, the defense of justification should be preferred over self-defense, as IHL is lex specialis in an armed conflict.

The third scenario is similar to the second in that the soldier is charged with murder of a man who raised a rifle and pointed it at the soldier, except this scenario takes place in an international armed conflict and the man with the rifle is a member of the enemy armed forces and is wearing a uniform. At his trial, the soldier can clearly claim the defense of justification: the soldier’s actions are permissible under IHL because he is attacking an enemy combatant so his actions would be excused under the justification defense. The concept of combatant immunity applies to his actions. Unlike scenario two, however, the soldier cannot claim criminal self-defense because the actions of the enemy soldier are not wrongful in that he also has the legal right under IHL to kill the US soldier. The difference between scenario two and scenario three is that in scenario two, the man who was shot had no legal authority to use force against the US soldier so his use of force was wrongful. In scenario three the actions of the enemy soldier were not wrongful so a claim of self-defense would likely succeed in scenario two, but fail in scenario three.

While this is a technical argument that would have little significance in an actual criminal case, it is important to note because it illustrates why individual self-defense on the battlefield is a limited authority. It will generally apply in only two situations – against someone trying to harm a person for motives not connected to the ongoing armed conflict or in non-international armed conflicts against members of organized armed groups or civilians taking a direct part in hostilities when their conduct creates an immediate threat of physical harm.

The SROE were initially intended to provide commanders with guidance on how to respond in national self-defense in the event their units were attacked outside an armed conflict. Over time, this delegation of authority to act in national self-defense has been conflated with the criminal law concept of individual self-defense. Unfortunately, this change coincided with the US fighting multiple non-international armed conflicts. Rather than issuing ROE to properly address fighting civilians and members of organized armed groups, the US left its soldiers with using confusing self-defense terminology. The result is a confusing self-defense landscape, where soldiers, commanders, and in some cases, their legal advisors, are unsure what constitutes using force under IHL or in self-defense.