The Fourth Industrial Revolution will provide insurgents and terrorists with capabilities that, until very recently, were the preserve of large, powerful, wealthy states. The convergence of new technologies will provide them access to relatively cheap, long-range, autonomous weapons. To define the problem this presents to the United States, this paper will first explore the technologies—powerful small warheads, autonomous drones, task-specific artificial intelligence, and advanced manufacturing—that are providing increased range, numbers, and lethality for dramatically lower cost today.