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In its current usage as a targeted killing platform, the Remotely Piloted Aircraft (RPA) or ‘drone’ represents a fundamental challenge to the idea of proportionality as discussed in just war theory. In combining surveillance and strike into a singular package devoid of risk to its operators, RPA have become a destabilizing force to the ideas of justice in war–jus in bello–and justice of war–jus ad bellum–due to the shift in risk calculation that their unique capabilities allow. The concept of proportionality is understood as managing the use of force such that it does not become a greater evil than the one it is fighting. In removing any threat to operators’ lives, the drone critically unbalances the notion of proportionality and risks making the choice to deploy lethal force seductively easy.

Rapid deployment of RPA capability has left a wake of unaddressed technical and strategic problems. The very notion of the accuracy of RPA, and their subsequent ability to be discriminate within the confines of proportionality, is oversimplified and misunderstood. The ability of drones to provide surveillance for their own strikes has created a fallacious assessment of their true accuracy. While RPA systems may be technically accurate, overall accuracy relies on a myriad of factors to ensure usage on the “correct” target. Intelligence failures, targeting failures and even technical issues can greatly reduce the accuracy of the weapon in practical terms.

Current targeted killing programs–most notably those of the United States–are creating strains on international law. In violating sovereign nations’ airspace and killing its own citizens without trial via RPA, the U.S. is setting precedents, which could threaten the very balance of the international system. The U.S. currently has a monopoly on the usage of RPA in combat, but like the computers that power them and the networks that connect them, drones are getting more capable and more affordable at a staggering rate. In fielding RPA without any discussion of limits, there is a real risk of atrocious behavior by states and non-states alike, and no codified way to assess such actions.

Looking toward the future, the international community would be prudent to begin discussions on acceptable limits for RPA usage and legal frameworks for managing violations of just war traditions committed via drone. Policing such limits would prove difficult, but absent any framework, the risk is that drones will be used to violate international norms without recourse for those affected, aside from direct retaliation. Determining a “middle ground” approach to the usage of RPA– one that squares states’ desires with ethical requirements–is essential to the continued stability of the international system. 

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