Treason, Terrorism, and Betrayal: Why Individuals Cross the Line Hardcover – July 22, 2025

“[Costanza] challenges readers to think beyond stereotypes of traitors as simple villains and instead consider the complex interplay of personal motive, institutional pressure, and geopolitical context.... A worthy contribution.” ―Sean Wiswesser, The Cipher Brief“Highly recommended.” ―Choice “Ambitious, well-sourced, and eminently useful.... A unique and important contribution to the study of an enduring problem.” ―Joseph Gartin, Intelligence Officer’s Bookshelf A must read for those interested in insider threats and their impact on U.S. National Security." ―Keith Cozine, St. John's University"In his thoughtful book, Costanza looks across disciplines and methodologies for insights into why an individual might decide to 'cross the line'―and the limits on our understanding of such complex human behavior…. A valuable resource, not only for the case studies and analysis it provides, but also for the key challenges it lays out for the future." ―Michelle Van Cleave, former head of US counterintelligence"Rejecting the idea that the actions of individuals who have harmed or threatened the security of the United States can be explained simply, Costanza argues convincingly that a complex interplay of personal and professional issues motivated those individuals to 'cross the line.'"―Gregory Moore, Notre Dame College"A fascinating read…. The detailed descriptions of each of the 'betrayers' are not just informative, but revelatory of the different variety of motivations that drive each individual to treason and terror.” ―Stephen Kappes, former head of counterintelligence and deputy director of the Central Intelligence Agency Aldrich Ames. Timothy McVeigh. Kim Philby. Julius and Ethel Rosenberg. Edward Snowden. These are just a few of the people well known for willfully jeopardizing US national security. What compelled them and others like them to commit such acts? Can the danger be detected before it’s too late? William Costanza employs an interdisciplinary approach to reveal the many intertwined factors that might lead a person down a path to espionage, terrorism, or betrayal. Drawing on a wide range of detailed case studies, he proposes tools for better understanding why some individuals "cross the line" and, as a result, for better deterring threats.CONTENTS: Crossing the Line.Espionage, Treason, and Counterintelligence.Spying for the Enemy: Case Studies.Radicalization and Violent Extremism.Jihadis and Far-Right Radicals: Case Studies.The Insider Threat: Unauthorized Release of Protected Information.Insiders Who Crossed the Line: Case Studies.Mitigating the Threat. Read more