In Why Leaders Lie, John Mearsheimer provides the first systematic analysis of lying as a tool of statecraft, identifying its different forms, the reasons for it, and the potential costs and benefits. Drawing both on historical and present-day examples, he argues that leaders often lie for good strategic reasons - as Roosevelt and Churchill did in World War Two - which makes blanket condemnation unrealistic and unwise. And there is always an important difference between lying to another state and lying to one's own people, as in the invasion of Iraq. John Mearsheimer discovers that interstate lying has always been unusual; due to the distrust among great powers, outright deceit is difficult to pull off, and sometimes backfires. Leaders more frequently mislead their own publics and democratic leaders like our own do it more often than dictators. This book explains why. There has never been a full discussion of international lying. Now a leading expert fills the gap with this richly informed and powerfully argued book. Why Leaders Lie provides a template for understanding the real world of high-level decision making.