Why We Fight: The Battle For China & War Comes To America (1945) DVD
 
Why We Fight is a series of seven documentary films produced by the US Department of War from 1942 to 1945, during World War II. It was originally written for American soldiers to help them understand why the United States was involved in the war, but US President Franklin Roosevelt ordered distribution for public viewing.
 
Academy Award-winning filmmaker Frank Capra, daunted but impressed and challenged by Leni Riefenstahl's 1935 propaganda film Triumph of the Will, worked in direct response. The series faced various challenges, such as convincing a noninterventionist nation to get involved in the war and to become an ally of the Soviet Union. Many entries feature Axis powers' propaganda footage from up to 20 years earlier, recontextualized to promote the Allies.
 
Although primarily edited by William Hornbeck, some parts were re-enacted "under War Department supervision" if no relevant footage was available. Animated segments were produced by Walt Disney Productions, and the animated maps followed a convention of depicting Axis-occupied territory in black.
 
The Battle of China (1944, 62min 16s) shows Japanese aggression such as the Nanking Massacre and Chinese efforts such as the construction of the Burma Road and the Battle of Changsha. Capra's synopsis: "Japan's warlords commit total effort to conquest of China. Once conquered, Japan would use China's manpower for the conquest of all Asia."
 
War Comes to America (1945, 64min 20s) shows how the pattern of the Axis powers's aggression turned the American people against isolationism. Capra's describes: "Dealt with who, what, where, why, and how we came to be the USA—the oldest major democratic republic still living under its original constitution. But the heart of the film dealt with the depth and variety of emotions with which Americans reacted to the traumatic events in Europe and Asia. How our convictions slowly changed from total non-involvement to total commitment as we realized that loss of freedom anywhere increased the danger to our own freedom. This last film of the series was, and still is, one of the most graphic visual histories of the United States ever made.