Dr. Elisabeth Hoffberger-Pippan, Researcher, Peace Research Institute Frankfurt (PRIF) - Written evidence (AIW0002)

a)  Is existing International Humanitarian Law (IHL) sufficient to ensure any AWS act safely and appropriately?

No. Existing IHL is insufficient to address the most pertinent questions relating to AWS.

The debate on AWS in the UN-GGE has mainly centered upon the question of how international humanitarian law (IHL) applies to AWS and how the rules governing targeting decisions should be applied and interpreted when outsourcing core competences to machines. The UN-GGE Guiding Principles on AWS[1] adopted in 2019, a legally non-binding but politically highly relevant document, emphasize that IHL continues to apply fully to AWS:

(a)                        International humanitarian law continues to apply fully to all weapons systems, including the potential development and use of lethal autonomous weapons systems.

The terminology “including the potential development” insinuates that IHL would cover scenarios where AWS have not yet been deployed on the battlefield. But we have to be very careful with this line of reasoning. IHL not only has geographical but also temporal limits. States Parties to the GGE need to consider that as a general rule, IHL applies once an armed conflict has commenced.

Two practical examples should flesh out the pertinence of the legal questions surrounding the temporal scope of application of IHL.

Example 1: State A and B are at peace. But given increased tensions between the two countries over the last months, State A decides to intercept and later shoot down an AWS by using an AWS itself. No harm other than damage to State B’s property has been caused.

Example 2: State A attacks State B with a missile that is intercepted by a highly sophisticated autonomous – defensive – weapon system by State B. Which legal regime would State B have to apply? Would that be a matter of the ius ad bellum, the ius in bello, or both?

In the first example, we can see that a comparatively minor incident (depending on the individual circumstances ruling at that time) occurred where no humans have been injured and no lives have been lost. Would such a “low scale” resort to force already be covered by IHL? And if yes, why? Example two adds another layer of complexity as State B clearly acts in self-defense. Would this scenario be covered by IHL?

Analysis example 1: The majority of legal commentators takes the view that IHL already applies to the first shot (first shot theory)[2] and that no intensity threshold is required for the force that has been used. There are, however, authors who clearly disagree[3] arguing that IHL only applies if a certain threshold of force has been reached. A third group of authors argue that a certain threshold level for the use of force is irrelevant but IHL does not apply to the first shot.[4] So how would this translate into our discussion on AWS and the applicability of IHL? The first group of commentators would argue that any use of force, whether by using crewed, un-crewed, remotely piloted or fully AWS, including the first shot, is covered by IHL. The second group, however, would probably argue that the relevant threshold of harm might not yet have been reached. Such a scenario, arguably, would be covered by International Human Rights Law (IHRL). But would human rights be relevant in case machines are fighting against each other? Furthermore, the extraterritorial applicability of IHRL in scenarios such as air warfare is a highly disputed topic.[5] The third group of commentators would argue that no threshold is required but that only IHRL applies.

Analysis example 2: The second example adds another layer of complexity. Since State B is acting in interceptive self-defense within the meaning of Article 51 UN-Charter, the legal rules on the ius ad bellum in case of self-defense (necessity, proportionality) applies. But what about IHL? There are various commentators arguing that in case of self-defense IHL (with similar but by far not identical principles, such as necessity and proportionality) applies in parallel to the ius ad bellum.[6]  This approach was also taken by the International Court of Justice’s Advisory Opinion on the Legality of the Threat or Use of Nuclear Weapons[7]. But there are still open questions that are far from clear. What if, for example, a non-state armed group deploys a missile against State B which then intercepts with an AWS? Would the ius ad bellum or in bello still apply an if so, in which way?

Conclusion: All these questions have existed before the debate on AWS has even started. But AWS add another layer of complexity. My main point is that additional rules on the use of AWS would be helpful to better grasp these challenges in order to ensure that AWS are used in line with military, but also legal and ethical considerations.

Dr. Elisabeth Hoffberger-Pippan

Peace Research Institute Frankfurt (PRIF)

March 2023

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