Lethal Autonomous Weapons Systems

Over the past decade, there has been a proliferation of remotely piloted aircraft or “drones” being used on the battlefield. Advances in technology are going to continue to drive changes in how future conflicts will be waged. Technological innovation, however, is not without its detractors as there are various groups calling for a moratorium or ban on the development and use of autonomous weapons systems. Some groups have called for a prohibition on the development, production, and use of fully autonomous weapons through an international legally binding instrument, while others view advances in the use of technology on the battlefield as a natural progression that will continue to make weapons systems more discriminate. The unanswered question is, which point of view will be the right one? This chapter approaches this question by addressing the meaning of “autonomy” and “autonomous weapons systems.” In addition, this chapter looks at the U.S. Department of Defense’s vision for the potential employment of autonomous systems, the legal principle applicable to these systems, and the weapons review process.

Hybrid Warfare, Law, and the Fulda Gap

The law constitutes an integral and critical element of hybrid warfare. Law conditions how we conceive of and conduct war. By drawing a line between war and peace and between permissible and impermissible uses of force, the international legal framework governing warfare stabilizes mutual expectations among the warring parties as to their future behavior on the battlefield. Hybrid adversaries exploit this stabilizing function of the law in order to gain a military advantage over their opponents. They do so by failing to meet the relevant normative expectations, by using a range of means, including noncompliance with the applicable rules, by instrumentalizing legal thresholds, and by taking advantage of the structural weaknesses of the international legal order, while counting upon the continued adherence of their opponents to these expectations. The overall aim of hybrid adversaries is to create and maintain an asymmetrical legal environment that favors their own operations and disadvantages those of their opponents. This poses two principal challenges, one specific and one systemic in nature. Law is a domain of warfare. Nations facing hybrid threats should therefore prepare to contest this domain and strengthen their national and collective means to do so. At the same time, the instrumentalization of law poses profound challenges to the post–Second World War international legal order. Nations committed to that order cannot afford to respond to hybrid threats by adopting the same means and methods as their hybrid adversaries without contributing to its decay.

Personal Self-Defense and the Standing Rules of Engagement

The U.S. military Standing Rules of Engagement (SROE) restrict the use of force in armed conflict to either self-defense or “mission-specific” rules of engagement, which refer to the use of force against members of enemy armed forces or organized armed groups that have been “declared hostile.” This bifurcation of authority works well in an international armed conflict, where the enemy force is uniformed and easily distinguished. In these circumstances, the overwhelming number of engagements are against identified hostile forces. In many non-international armed conflicts, however, combatants actively attempt to camouflage their status, and U.S. forces find themselves engaging enemy forces under a self-defense framework. This creates problems. Consider, for example, a situation where three individuals of unknown affiliation launch an attack against a U.S. military convoy in Afghanistan. After a short engagement, the attackers get in a van and speed away from the attack site. The U.S. convoy is disabled, but an unmanned aerial vehicle tracks the van as it retreats into the desert. Thirty minutes later an AH-64 Apache attack helicopter arrives on scene above the still-retreating van. Can the Apache attack the vehicle? The van is retreating and poses no threat, thus self-defense principles would not allow for the use of force, despite the fact that the occupants are clearly directly participating in hostilities. This chapter addresses three questions: Why are the SROE drafted in this manner? What is the basis in the law for the SROE’s approach to self-defense? What are the problems presented by this approach?

Accounting for the Complexity of the Law Applicable to Modern Armed Conflicts

It is almost trivial to observe that the law applying to modern armed conflicts is full of complexities. Such complexities are, after all, the bread and butter of legal academics, who have produced mountains of books and articles on the various relevant topics, but the extent of these complexities can be overstated. While legal academics debate the finer points of the interaction between international humanitarian law (IHL) and international human rights law (IHRL), in the majority of today’s armed conflicts the law is reasonably practical and clear. It might not be complied with, but that is not because of its supposed complexity or lack of clarity. If, for example, the parties to armed conflicts with the highest cost in human lives and property (e.g., in Syria or Yemen) observed only the bare fundamentals of the principle of distinction, the world would be spared much suffering. Noncompliance has little to do with the law’s complexity. But complexity is nonetheless a major feature of a subset of modern armed conflicts, especially those involving foreign intervention by Western powers. The purpose of this chapter is to clarify our understanding of how complexity works, where it comes from, and how it is managed. To do so, this chapter first develops two themes: the multiple causes of complexity and the decentralized system for managing this complexity. These themes are then explored in more detail in the context of the law on the use of force, or jus ad bellum, IHL, and IHRL.

Fragmented Wars

The use of force against armed groups located in other States is not new, but began receiving heightened attention as a result of U.S. operations in Afghanistan following the attacks of September 11, 2001. The high-profile nature of these events, the resoluteness with which the United States asserted its right to self-defense against an armed group, and the international support that it received all led to increased attention to the surrounding legal matters. Much of the debate centered upon the basic question of whether a State has a right to self-defense in response to attacks perpetrated by a non-State actor located in the territory of another State, absent attribution of the attack to the other State. Other important issues included the classification of hostilities between the State and such a group, and rules governing the conduct of the parties. This chapter sets out to draw together the threads of these debates from the last fifteen years, to analyze new questions that have emerged, examine how they impact upon each other, and suggest a way forward for overcoming legal challenges.

The Law and Policy of Human Shielding

The phenomenon of human shields challenges many of the core tenets of international humanitarian law (IHL), including its careful dialectic between the imperatives of humanity and military necessity. Although the concepts of distinction, precaution, and proportionality are well established in the abstract, any consensus on how these rules apply to situations involving human shields is showing signs of fraying. The IHL literature offers competing approaches for evaluating the legal consequences surrounding the use of human shields for the party that stands to benefit from the presence of shields and for the party seeking to engage the shielded military objective. In particular, the application of the rules of distinction and proportionality has become the subject of intense debate about whether human shields are entitled to full civilian protections when it comes to targeting. This legal indeterminacy is being strategically generated and increasingly deployed by a range of implicated actors and norm entrepreneurs in an effort to loosen the restrictions on targeting, to excuse civilian deaths, and to shield armed actors from legal responsibility—all to the detriment of civilian protection. This chapter distinguishes forms of human shielding and sets out the legal framework in treaty and customary international law. It then evaluates the various arguments that address the phenomenon of human shielding. This chapter concludes that the safest course for parties committed to the values underlying IHL is to adopt a policy that treats all human shields as civilians, unless there is irrefutable proof of willing participation in hostilities.

Be Careful What You Ask For

Aleppo, Syria—a city that will join the infamous likes of Nanking, Stalingrad, Manila, Berlin, Hue, Panama City, Mogadishu, Grozny, and Donetsk as one of modern history’s worst urban war zones. Much of the destruction in this city is the result of indirect fires and air-delivered munitions. Indeed, this is the case in Aleppo; the now-infamous “barrel bomb” has become synonymous with indiscriminate Syrian government attacks against rebel-held areas of the city. In response to the humanitarian dangers associated with the use of such weapons in urban and built-up areas, there is a growing trend among international humanitarian law advocates to severely restrict—or even ban outright—the use of fires, high-explosive munitions, and associated weapons systems in built-up civilian population centers. These humanitarian initiatives reveal that for proponents of such restraint, the “problem” of high explosives in populated areas, whether delivered by indirect fire systems or air assets, is critical. The core premise of this chapter is that new restrictions on urban fires may actually exacerbate civilian risk and that fires in support of urban operations are not only operationally essential, but may, when properly employed, actually reduce risk to civilians and civilian property. Accordingly, civilian risk mitigation efforts should continue to focus on enhancing commitment to and compliance with already existing attack precautions and law of armed conflict (LOAC) targeting obligations.

The Use of Force in Armed Conflicts Conduct of Hostilities, Law Enforcement, and Self-Defense

In modern warfare, military forces are expected to use lethal or potentially lethal force in a variety of contexts ranging from combat operations against the adversary to maintaining law and order or responding to imminent threats to life or limb. In practice, it may not be easy to distinguish between these various situations, which may overlap, as for instance when fighters hide among rioting civilians or demonstrators. Situations of violence may also be volatile and quickly evolve from mere civilian unrest to armed clashes. This factual or operational complexity is accompanied by a legal complexity. Different legal regimes and “paradigms” govern the use of force. From an international law perspective, the use of force by armed forces and law enforcement officials is governed by two different paradigms: the conduct of hostilities paradigm, derived from international humanitarian law (IHL), and the law enforcement paradigm, mainly derived from international human rights law (IHRL). Additionally, armed forces frequently refer to the concept of self-defense at various levels (State, unit, personal) as encompassed in numerous rules of engagement. The legal sources of these concepts and interplay with IHL and HRL remain often unsettled and deserve being clarified. This chapter aims at addressing the legal complexities in identifying governing use of force rules through the analysis of various situations/scenarios that are typical of contemporary military operations.

Cyber National Security

When the first host-to-host message was sent across the ARPANET in October 1969, few could have fully anticipated the degree to which the internet, and now the internet of things, would explode across the globe and revolutionize nearly every facet of public and private life. Nor could anyone have predicted the degree to which it would establish an entirely new realm—cyberspace—through which States could engage in traditional, and not-so-traditional, statecraft and conflict. However, it is now clear that States have fully embraced cyber operations as a means to pursue their national interests and gain low-cost asymmetric advantages over their adversaries. Cyberspace has become a new instrument of statecraft and presents novel and challenging questions about the applicability of existing legal orders. Adversaries are leveraging and exploiting the numerous technical, policy, and legal ambiguities surrounding cyberspace operations to conduct a range of intrusive and increasing aggressive activities. While some of these cyber operations have been conducted as part of ongoing armed conflicts, the vast majority have taken place in the so-called gray zone—the far more uncertain space between war and peace. Also known as gray-zone challenges or gray-zone conflicts, these activities are more accurately understood as actions that are coercive and aggressive in nature and rise above normal, everyday peacetime geo-political competition, yet remain below the threshold of war. This chapter will identify and consider some of the more challenging domestic and international legal issues raised by the conduct of cyber operations in the gray zone between peace and war.

New Technologies and the Interplay between Certainty and Reasonableness

Underlying ongoing and intensive efforts to understand how the law of armed conflict (LOAC) does, could, and should apply to the use of new technologies is an equally comprehensive effort to understand precisely what these new weapons are and how they work. Many new technologies introduce unique questions for human understanding, often driven and exacerbated by the fact that the technology is out of sight or out of reach of human senses, making actual concrete understanding of how it works challenging and elusive. Effective legal analysis and guidance for the use of any weapon rests on an accurate understanding of how that weapon works. This uncertainty and quest for more determinative information about the nature of certain new technologies has the potential for unintended and possibly untoward effects on the very implementation and application of the law itself—in effect, it has the potential to change the law. As in many other legal regimes, critical components of legal analysis and interpretation in LOAC involve reasonableness: that is, whether the actions of a commander were reasonable in the circumstances prevailing at the time. In contrast, the need to understand how a new technology works and what it might do in a given situation, particularly with regard to autonomy, is not an inquiry resting on reasonableness, but rather on the desire for as much certainty as possible. This chapter examines how the development and use of new technologies in weapons may impact the balance between reasonableness and certainty in LOAC, in particular whether a quest for certainty will bleed over into the application and interpretation of the law and, over time, affect the development and understanding of the law itself.