This article, by Prof. Peter Asaro, Co-founder and Vice-Chair of the International Committee for Robots Arms Control, was published in the International Review of the Red Cross in 2012. It considers the literature concerned with establishing an international prohibition on autonomous weapon systems. It seeks to address concerns expressed by some scholars that such a ban might be problematic for various reasons. It argues in favour of a theoretical foundation for such a ban based on human rights and humanitarian principles that are not only moral, but also legal ones. In particular, an implicit requirement for human judgement can be found in international humanitarian law governing armed conflict.