Post-Cold War, armed groups of various kinds began to proliferate and the patterns of conflict were changing, but only a handful of specialists interpreted these developments as a harbinger of a changing international security and conflict environment. In the forefront was Martin van Creveld who contended that non-state actors would increasingly challenge the dominance of state power. With the exception of the U.S. Marine Corps, throughout the 1990s the line of reasoning advanced by van Creveld and a handful of others was persona non grata in the institutions that comprise the U.S. government's national security system. They rejected this argument as flawed and devoted few resources and attention to the challenges posed by terrorists, criminal syndicates and other non-state armed groups. They did so based on two main propositions: that nothing about these groups was new and that these groups did not pose a first-order security challenge to major states to include the United States, but rather they were ancillary security nuisances. Each of these arguments ignored the changing context in which armed groups operated in the 1990s and into the 21^st Century that now make it possible for an armed group to challenge even major states strategically and in some cases to do so across the globe.