The American public faces an unstable landscape in the wake of 21st century terrorism. Evolutionary trends in transnational and domestic terrorism indicate a shift toward increasingly violent acts as law enforcement and intelligence agencies apply pressure to these organizations. The collapse of nation-states, the splintering of transnational terror groups and criminal enterprise along with a resurgence of domestic extremism will contribute to a new era of ultra-terrorism in which no target is off-limits. The next generation of terrorist will evolve tactics derived from the active shooter,...