A propaganda film is a film, either a documentary-style production or a fictional screenplay, that is produced to convince the viewer of a certain political point or influence the opinions or behavior of people, often by providing deliberately misleading, propagandistic content.
The development of Russian cinema in the 1920s by such filmmakers as Dziga Vertov and Sergei Eisenstein saw considerable progress in the use of the motion picture as a propaganda tool, yet it also served to develop the art of moviemaking. Eisenstein's films, in particular The Battleship Potemkin, are seen as masterworks of the cinema, even as they glorify Eisenstein's Communist ideals.
The 1930s and 1940s, which saw the rise of totalitarian states and the Second World War, are arguably the "Golden Age of Propaganda". During this time Leni Riefenstahl, a filmmaker working in Nazi Germany, created what is arguably the greatest propaganda movie of all time: Triumph of the Will, a film commissioned by Hitler to chronicle the 1934 Nazi Party rally in Nuremberg. Despite its controversial subject, the film is still recognized today for its influential revolutionary approaches to using music and cinematography.
In the United States during World War II, filmmaker Frank Capra created a seven-part series of films to support the war effort entitled Why We Fight. This series is considered a highlight of the propaganda film genre. Other propaganda movies, such as Thirty Seconds Over Tokyo and Casablanca, have become so well-loved by film viewers that they can stand on their own as dramatic films, apart from their original role as propaganda vehicles.
Many of the dramatic war films in the early 1940s in the United States were designed to create a patriotic mindset and convince viewers that sacrifices needed to be made to defeat "the enemy." One of the conventions of the genre was to depict a racial and socioeconomic cross-section of the United States, either a platoon on the front lines or soldiers training on a base, which come together to fight for the good of the country. In Italy, at the same time, film directors like Roberto Rossellini produced propaganda films for similar purposes.
For more discussion of propaganda and some examples of it in short films from the United States, see the 10-volume CD-ROM collection Our Secret Century. For a satirical subversion of the United States military's 1960s propaganda regarding the safety of radioactive materials, see The Atomic Cafe.