Is There a Right to Use Military Force Below the Threshold of War? Emerging Technologies and the Debate Surrounding jus ad vim

From a technical point of view, remote-controlled drones and “autonomous” weapons systems are doubtlessly different. But both promise a “more precise” use of potentially deadly force. In seeking to justify the use of such technologies, firstly the social context in which they are deployed must be taken into account. Secondly, blanket attempts to argue that their use is justified – or that they should be banned – based on relevant legal norms or elaborate deontological reasoning, are for the most part not very convincing. The use of such technologies therefore has to be looked at in the context of the legitimacy of military force per se.

Along with difficulties of definition, the latest developments in weapons technology raise ethical quandaries, such as their use as weapons of mass destruction or the possible proliferation of “killer drones” with facial recognition software. However, as long as morally acceptable uses are conceivable, the question then is what normative framework can and should govern these cases.

The construct of ius ad vim – a “right to limited force” – was first proposed by Michael Walzer. The idea is to give states more options, particularly in response to terrorist attacks below the threshold of war. Yet this proves to be worrying in several respects. Due to its specific location in traditional just war theory, ius ad vim owes much to the idea of state authority (as being the only legitimate authority), and is found wanting compared to revisionist approaches. An associated issue is that it entrenches a right that is a de facto benefit to technologically capable states. This is not mitigated either by the newly introduced principle of “maximal restraint”, or by the only seemingly modest goal of a “truncated victory”. We should instead ask whether the use of a technological advantage legitimized in this way, and the tendency to “distance” one’s own troops from the conflict, is not more likely to fuel a latent permanent conflict.