Unlike conventional weapons or remotely operated drones, autonomous weapon systems can independently select and engage targets. As a result, they may take actions that look like war crimes--the sinking of a cruise ship, the destruction of a village, the downing of a passenger jet--without any individual acting intentionally or recklessly. Absent such willful action, no one can be held criminally liable under existing international law.
Criminal law aims to prohibit certain actions, and individual criminal liability allows for the evaluation of whether someone is guilty of a moral wrong. Given that a successful ban on autonomous weapon systems is unlikely (and possibly even detrimental), what is needed is a complementary legal regime that holds states accountable for the injurious wrongs that are the side effects of employing these uniquely effective but inherently unpredictable and dangerous weapons. Just as the Industrial Revolution fostered the development of modern tort law, autonomous weapon systems highlight the need for "war torts": serious violations of international humanitarian law that give rise to state responsibility.
INTRODUCTION I. INTERNATIONAL ACCOUNTABILITY IN ARMED CONFLICT A State Responsibility in Armed Conflicts B. The Rise of Individual Criminal Liability 1. Historic Foundations 2. The Performative Function of Criminal Law C. The Unnecessary Displacement of State Responsibility II. THE ACCOUNTABILITY GAP A. Introducing Autonomous Weapon Systems 1. The Killer Robots Are Here 2.... And More Are Coming 3. Inherent Unpredictability and Inevitable Accidents B. No Individual Criminal Liability 1. The Willful Action Requirement 2. No Direct Individual Liability 3. No Indirect Individual Liability 4. The Problems with Criminalizing Negligence III. INTRODUCING "WAR TORTS" A. Why "War Torts"? B. Accountability for Autonomous Weapon Systems 1. Holding States Responsible 2. The Argument for Strict Liability 3. Forms and Forums 4. The Time Is Now 5. A Useful Test Case CONCLUSION INTRODUCTION
"There can be no justice in war if there are not, ultimately, responsible men and women! (1)
Imagine a marine autonomous weapon system, armed with torpedoes, designed to patrol within a preset region and attack anything it identifies as an enemy warship. Is anyone liable if it sinks a cruise ship, resulting in the deaths of all aboard? Or envision a mobile, land-based autonomous weapon system, meant to provide force protection, that enters a remote village and kills every man, woman, and child it encounters. Who is responsible for that massacre? On July 17, 2014, Malaysia Airlines flight MH17 was shot down over eastern Ukraine, resulting in the deaths of all 298 individuals on board. (2) Many were quick to argue that this action should have spurred prosecution, either as a war crime under international law or as murder under domestic criminal laws. (3) But if an autonomous weapon system had fired the missile that downed the plane, could anyone be held accountable?
Autonomous weapon systems are fundamentally different from prior forms of weaponry: their capacity for self-determined action makes them uniquely effective and uniquely unpredictable. Unlike conventional weapons or remotely operated drones, an autonomous weapon system can select and engage targets without human direction or oversight. (4) And unlike landmines, trip-wire sentry guns, or other automated weapon systems, autonomous weapon systems do not simply react to preset triggers. Instead, they gather information from their environment and make independent calculations as to how to act. (5) The sheer complexity of autonomous weapon systems' methods for making these determinations may make it impossible for human beings to predict what the systems will do, (6) especially to the extent they operate in complex environments and are subject to various types of malfunction and corruption. More advanced autonomous weapon systems might even "learn" from in-field experiences or make probabilistic calculations. (7)
Given their destructive capacity and their inherent unpredictability, if autonomous weapon systems continue to be fielded, they will inevitably be involved in an accident with devastating and deadly consequences. Assuming that no one intended for the accident to occur or acted recklessly, it is unlikely that any person could be held individually liable under existing international criminal law. By definition, war crimes--serious violations of international humanitarian law that give rise to individual criminal liability(8)--must be committed by a person acting "willfully," which is usually understood as acting intentionally or recklessly. (9) By challenging the presumption that serious violations of international humanitarian law will not occur absent willful human action, autonomous weapon systems threaten to destabilize nearly seventy years of efforts to establish international criminal law.
Individual criminal liability for war crimes grew from a deep-seated desire to hold individuals accountable for atrocities and to discourage future occurrences. (10) Criminal law is useful for creating and enforcing prohibitions, and it therefore provides an appropriate liability regime for genocide, slavery, massacres, systematic rape, and other such outrages. But while autonomous weapon systems are capable of committing serious violations of international humanitarian law with tragic consequences, they are too useful to be criminalized. Not only do they offer a seductive combination of distance, accuracy, and lethality, this uniquely effective weaponry may prove to be more "humane" than human beings on the battlefield. Given their inherent value and their attendant risk, what is needed is a legal regime that regulates, rather than prohibits, the use of autonomous weapon systems. Enter tort law.
Oddly, there is no well-developed field of international tort law. Many domestic legal subjects have an international corollary: there is civil rights law and international human rights law, intellectual property law and international intellectual property law, contracts and bilateral trade treaties. But tort law--the legal regime governing those noncontractual civil wrongs for which an individual can seek redress--does not have an obvious international doppelganger. (11) Environmental lawyers have long been trying to create international tort liability for transnational environmental damage, but their efforts have borne little fruit. 12 Article 75 of the Rome Statute of the International Criminal Court (ICC) provides that the "Court may make an order directly against a convicted person specifying appropriate reparations to, or in respect of, victims." (13) While this marks the first time in the history of international law that individual victims may seek remedies before an international tribunal, (14) the ICC appears unwilling to endorse employing Article (75) to justify tort-like compensation. (15) The U.S. Alien Tort Statute (ATS) is unusual domestic legislation in that it recognizes and creates federal subject matter jurisdiction for the prosecution of individuals for international torts. (16) Scholars have proposed augmenting the ATS to create enterprise or group liability for international torts, (17) but the possibility of tort liability in international law (as opposed to U.S. jurisprudence) remains underexplored. (18)
While the reasons for the dearth of scholarship on international tort liability are unclear, two facts are apparent. As evidenced by the varied and extensive ATS litigation in the United States, there is a strong desire to hold entities accountable for actions that fall short of incurring criminal liability. And yet, given the relatively undeveloped nature of the legal structures, states apparently have little interest in creating effective international tort liability regimes. Considering the lack of international tort law, it is not surprising that no one has yet evaluated whether it might be useful in addressing the autonomous weapon systems accountability gap. (19)
However, this accountability gap is precisely the kind of problem tort law is designed to solve. (20) Pressures similar to those that fostered the transformation of domestic tort law over a hundred years ago--the need to create a liability regime for the "stranger cases" resulting from the Industrial Revolution's significant, unintended, machine-caused injuries--are at play again, now in the international sphere. (21) As opposed to criminal law, which focuses on absolute prohibitions, tort law offers a means of regulating valuable but inherently dangerous activities and compensating injurious wrongs.
As is often the case with new technology, autonomous weapon systems expose a gap in the existing legal order. They highlight that, while there is an established (if not necessarily practically effective) means of holding individuals accountable for war crimes, the institutional processes of holding states accountable for their "war torts"...