The terrorist attacks of September 11, 2001, stimulated the most far reaching and deep reassessment of American national security strategy since the late 1940s. All of America's objectives, preferences, and methods were open to evaluation. The outcome of this process will shape U.S. strategy for years to come. In this study, conducted under the U.S. Army War College's External Research Associates Program, Dr. D. Robert Worley addresses the ways that the age of terrorism is affecting American grand strategy. He contends that terrorism has made many of the basic concepts of international relations and national security obsolete. Declaring war on a tactic; terrorism, erodes the clarity necessary for coherent strategy. Dr. Worley then develops what he calls a "guerra strategy" more appropriate for dealing with terrorism and other non-state threats.