The New York-based Human Rights Watch has announced the creation of an international coalition, which it hopes can push for a global treaty for a pre-emptive ban on artificially intelligent weapons before they can be fielded in battle. These “killer robots,” as the group calls them, are not yet being operated by any army in the world, though the pace at which drone technology and robotics are advancing has led to speculation that they could be developed within the next few decades. According to Humans Right Watch, which cites a report it co-authored with Harvard Law School in November of 2012, a fully autonomous machine that could select and fire upon a target selected of its own volition could be available within 20 years, if not sooner. Already the use of semi-autonomous weapons, such as aerial drones, has led to mounting criticism over the legal processes behind both the selection of foreign targets, and also their unilateral use on foreign soil. More recently in the US, there’s been a heated debate over whether they should be used on American citizens at all. According to a report produced by the Teal Group, in 2011 its market study estimated that in the coming decade worldwide spending on drones will reach $94 billion, with countries such as China looking to quickly close the gap with US technology.