[Ian Henderson is a group captain in the Royal Australian Air Force and is currently posted as the Director Military Law Centre and Deputy-Director Asia-Pacific Centre for Military Law. Bryan Cavanagh is a squadron leader in the Royal Australian Air Force and is currently posted as a legal training officer at the Military Law Centre and Asia-Pacific Centre for Military Law. This note was written in their personal capacities and does not necessarily represent the views of the Australian Government or the Australian Department of Defence. This is the second in a four-part series and the first post can be found here along with a response here.]
This is the second in a series of four posts that address the relationship between self-defence and LOAC. Yesterday we looked at when self-defence does and does not apply during a period of armed conflict. Today we discuss whether it is lawful under the criminal law concept of self-defence to cause incidental injury (aka, collateral damage) and whether self-defence imposes requirements similar to the ‘precautions in attack’ under article 57of Additional Protocol I (API).
Killing and injuring people that are not the object of the attack
Under the Law of Armed Conflict (LOAC), the rules relating to collateral damage are fairly easy to state – but difficult to apply. LOAC permits expected incidental loss of civilian life and injury to civilians (collateral damage), provided that the collateral damage is not excessive in relation to the military advantage anticipated to be gained from the attack. What then is the law relating to causing collateral damage when acting in self-defence?
A response in self-defence must be reasonable – so the question becomes – when (if ever) is it reasonable to kill or injure people who are not attacking you when responding to those who are? We had some difficulty in tracking down authority on point — in fact we could not find any reported Australian case law that addressed the issue — but domestic law of the US does. Case law in the US has held that while acting in self-defence can excuse injury or even death to a bystander in certain circumstances (eg, when not acting carelessly), self-defence does not excuse knowingly or recklessly injuring or killing a bystander (see Henwood v People, 54 Colo 188 (1913) ). Our conclusion is that it is highly likely that reasonableness under the law of self-defence imposes a higher standard of care on a military member than LOAC to avoid causing any injury or death to civilians. In other words, where a person acts ‘lawfully’ in self-defence, self-defence would operate as a successful defence to a charge relating to injuring or killing the attacker but not to a charge relating to injuring or killing a bystander.
To remove some confusion around this topic, we spelt out what ‘proportionality’ means under LOAC and self-defence. Proportionality under LOAC is used as a reference to the collateral damage equation mentioned above. Proportionality under self-defence is about the degree of force used in response to a threat. Proportionality under self-defence does not directly address the issue of collateral damage.
Precautions in attack
Article 57 of API sets out a number of precautions applicable to those who plan, decide and execute attacks. For example, they must do everything feasible to verify that the objectives to be attacked are military objectives; take all feasible precautions in the choice of means and methods of attack with a view to avoiding, and in any event to minimizing collateral damage, and to cancel or suspend an attack if it becomes apparent that the objective is not a military one or that the attack may be expected to cause excessive collateral damage.
We concluded that it is unclear whether the requirement of reasonableness under the law of self-defence would extend to requiring a military member to take all of the precautions set out in article 57. Even if it could be said that these requirements are relevant to the reasonableness assessment, they are unlikely to be as effective as protecting the civilian population as the explicit requirements set out in the article. We view this as unsurprising, as the law of self-defence was not developed to specifically address these types of issues that are unique to military operations.
In tomorrow’s post, we will compare how LOAC and the law of self-defence deal with a number of discrete issues like use of prohibited weapons, obedience to lawful commands, and a ‘duty’ to retreat.