In the 2001 Quadrennial Defense Review (QDR), Secretary of Defense Donald Rumsfeld introduced the concept of dissuasion, citing it as one of the “four key goals that will guide the development of US forces and capabilities, their deployment and use.” This view was subsequently confirmed in both The National Defense Strategy of the United States, published in 2005, and the 2006 QDR. Yet despite its apparent prominence in US defense planning, there is significant uncertainty and even confusion regarding a number of key issues: What exactly is dissuasion, and how does it differ from deterrence? How can the United States operationalize dissuasion; that is, what types of instruments can be used to dissuade both opponents and allies alike? Finally, what are the main impediments to a successful dissuasion strategy, and how can they be overcome? This report addresses each of these issues.