Psychological Operations (PSYOP) have been integral to U.S. military operations in times of war and peace. Using radio broadcasts, leaflets, loudspeakers, and other forms of media, the U.S. has directed PSYOP toward influencing the behavior of a target audience (TA), in order to influence their emotions, motives, and objective reasoning in support of the accomplishment of national aims and objectives. During war, tactical PSYOP is used to lower enemies' will to fight and ultimately lead them to surrender. Academics and practitioners have written a large body of literature over the last seventy years that addresses both successful and unsuccessful PSYOP. There has also been a large body of literature written about communication theory. What the literature fails to do is to address the important linkage between PSYOP and communication theory and how the relationship between the two affects the success or failure of PSYOP. Drawing from communication theory literature, this thesis builds a model for evaluating PSYOP products during the development phase. The thesis then applies this PSYOP model to Psychological Operations during the 1950-1953 Korean War, in an attempt to identify the conditions under which PSYOP products are crafted and deployed successfully. CHAPTER I * INTRODUCTION * A. BACKGROUND * B. METHODOLOGY * CHAPTER II * WHAT IS PSYOP? * A. DEFINING PSYOP * B. CRAFTING THE PSYOP MESSAGE * C. EVOLUTION OF PSYOP * D. FUTURE * CHAPTER III * COMMUNICATION THEORY * A. HISTORY OF COMMUNICATION THEORY MODELS * B. PSYOP MODEL * C. EVALUATION TOOL * D. PSYOP MODEL AS A LENS * CHAPTER IV * KOREAN WAR * A. CASE STUDIES: OPERATION MOOLAH, SAFE CONDUCT PASS LEAFLET, AND LOUDSPEAKER SURRENDER APPEAL * 1. Operation Moolah * a. Analysis of Operation Moolah * b. Operation Moolah PSYOP Matrix * 2. Safe Conduct Pass Leaflets * a. Analysis of the Safe Conduct Pass * b. Safe Conduct Pass PSYOP Matrix * 3. Loudspeaker Surrender Appeals * a. Analysis of Loudspeaker Surrender Appeals * b. Loudspeaker Surrender Appeal PSYOP Matrix * B. SUMMARY OF FINDINGS * CHAPTER V * CONCLUSION * A. THE FOUR VARIABLES * 1. In-Depth Knowledge of the TA * 2. Message * 3. Medium * 4. Receptiveness of the TA * B. THE THREE CASES * 1. Operation Moolah * 2. Safe Conduct Pass Leaflets * 3. Loudspeaker Surrender Appeal * C. IMPLICATIONS FOR PSYOP TODAY * LIST OF REFERENCES