During World War I and World War II, governments used propaganda techniques to influence public opinion and boost morale. This included posters, films, and radio broadcasts that promoted national unity, demonized the enemy, and encouraged enlistment. The use of emotional appeals and patriotic imagery aimed to rally citizens around the war effort. Key figures like George Creel in World War I and Elmer Davis in World War II led propaganda agencies that crafted messages to shape perceptions. These efforts often highlighted the sacrifices of soldiers and the importance of supporting the war, creating a sense of urgency and duty among the populace.