Why We Fight is the name of a propaganda series of seven newsreels commissioned by the United States government during World War II to convince the U.S. public about the need for American intervention.

Most of the newsreels were directed by Frank Capra, who was daunted and terrified by Leni Riefenstahl's propaganda film Triumph of the Will, and working in direct response to it. The series faced a tough challenge: convincing an isolationist nation of the need to become involved in the war, desegregate the troops, and ally with the Russians, among other things. In many of the newsreels, Capra and other directors spliced in Axis powers propaganda footage--recontextualizing it so it promoted the cause of the Allies instead. The films were edited mostly by William Hornbeck , and are some of the best examples of found-footage montage ever produced.

All of the films are one hour in length, except the Battle of Russia, which is two hours. All are available on DVD.

The seven newsreels are:

1. Prelude to War (1942) (Academy awarded as documentary)
2. The Nazis Strike (1942)
3. Divide and Conquer (1943)
4. The Battle of Britain (1943)
5. The Battle of Russia (1943)
6. The Battle of China (1944)
7. War Comes to America (1945)

The films refer several times to the highly disputed Tanaka Memorial, using it to raise American morale for protracted war as "Japan's Mein Kampf". Tanaka Memorial has since been shown to be a forgery.

In 2000 the United States Library of Congress deemed the newsreels "culturally significant" and selected them for preservation in the National Film Registry.

see also: War film, 'The Negro Soldier '