The conjecture 'that every aspect of learning or any other feature of intelligence can in principle be so precisely described that a machine can be made to simulate it' 1 has motivated scientists for more than half a century, but only recently attracted serious attention from political decision-makers and the general public. This relative lack of attention is perhaps due to the long gestation of the technology necessary for that initial conjecture to become a practical reality. For decades merely an aspiration among a small, highly skilled circle engaged in basic research, the past few years have witnessed the emergence of a dynamic, economically and intellectually vibrant field.From the beginning, national security needs drove the development of Artificial Intelligence (AI). These security needs were motivated in part by surveillance needs, especially codebreaking, and in part by weapons development, in particular nuclear test simulation. While the utilisation of some machine intelligence has been part of national security for decades, the recent explosive growth in machine capability is likely to transform national and international security, consequently raising important regulatory questions.Fueled by the confluence of at least five factorsthe increase in computational capacity; availability of data and big data; revolution in algorithm and software development; explosion in our knowledge of the human brain; and existence of an affluent and risk-affine technology industrythe initial conjecture is no longer aspirational but has become a reality. 2 The resulting capabilities cannot be ignored by states in a competitive, anarchic international system. 3