This paper looks at national security perceptions and policy in an age where well-known interstate threats have faded away. In their stead are a growing array of vulnerability-based, worst-case scenarios where murky groups turn modern society’s highest technologies and most deadly weapons against that society. Dr. William J. Durch argues the need to get beyond vulnerability-based policy and the risk of becoming hostage to our own worst fears, both to be sure that our limited resources address the right problems, and to promote the effective collaboration that has always been key to human security. Durch outlines a framework for measuring threat and building common perspective, a crucial ingredient in creating strong collaborative security efforts.