The "Shock and Awe" campaign that brilliantly launched Operation IRAQI FREEDOM ended with a thud as a right-sized invasion force proved too small to be an effective stability force once it removed Saddam Hussein from power. The Iraq conflict highlights the latest example where a senior leader dogmatically advocated the use of an inappropriate doctrine or unproven concept in war. This thesis explores the reasons why this occurs, looking at how mental traps expose senior leaders to decision errors during war planning and strategy development. The thesis uses the case study method to evaluate four recent conflicts, analyzing the propensity for military and political leaders to succumb to individual and group cognitive biases, thereby limiting their objectivity and causing them to support inappropriate doctrine or unproven concepts. The analysis illustrates how cognitive errors can lead to rigid thinking and a blurring of doctrine, dogma, and concept. Recommendations focus on institutionalizing organizational adaptability, increasing individual mental flexibility, and reinforcing the primary role of doctrine in war planning and strategy development.