Abstract/Summary

There is growing concern amongst international lawyers that the United States’ use of unmanned armed vehicles to conduct lethal targeting operations against non-state actors is setting a dangerous precedent for the future and might lead to an erosion of important rules under international law. Taking seriously these concerns, this article examines in more detail the potential precedent created by the US through its lethal drone strikes and the provided justifications, for the purpose of the development of jus ad bellum. In identifying the claims made by the US under different theories of customary international law as qualified practice or expressions of opinio juris that can lead to an alteration of the law should they be accepted by the international community, this article takes a first step towards a more extensive debate on the potential effects of the US drone strikes on the development of international law.