Throughout the history of film as a medium, it has been used by various governments for propaganda purposes. Beyond this, film has been used by countless individuals to convey specific viewpoints and encourage the audience toward a given opinion. Often, this is seen in the form of the documentary film genre, as the vast majority of the films in this genre are all attempting to convey a particular perspective on an issue that they are discussing. This can be seen especially in political documentary films such as: "Rolling Papers," "Boom Bust Boom" and "Enron": the smartest guys in the room. Each of these three films discuss a different topic from a specific perspective. In doing this, the filmmakers hope to influence the viewing public towards a particular political stance.
Propaganda films range the gamut of genre. The more readily obvious propaganda films tend to be produced and made by a particular branch of government. Typically, this branch of government will call itself a cultural authority of some sort. In the American film industry, big budget action films are often used as a somewhat more subtle form of propaganda, though this is not always the film-maker's desire or intention.
Often times, such films have their meaning entirely misconstrued intentionally to turn them into propaganda pieces whether they were intended to be by the film-makers behind them or not.
One such example of a film that is turned into being a propaganda film, whether intentional or not, is the recent film "American Sniper." In the film, audiences watch as a man turns to the military to become a member of the elite Special Forces group the Navy SEALS. The audience then watches as he goes on to become famous on the battlefield for his exceptional abilities as a sniper. Eventually, he retires from this career, only to then have difficulties after he returns home. Only for him to die in a tragic event when he was finally seeming to recover from his issues.
The basic story of this film then is a tragedy in which the hero of the film rises from unexceptional roots to become arguably one of the best in the world at his chosen career, only to return home and die senselessly. Yet, despite how this film seems to ultimately be a rather sad story about the difficulties of returning to the civilian world after having served in the military, it is often treated as a propaganda piece that only seems to encourage more people to want to emulate the hero of the film.
At this point, then, whether or not the filmmakers intended to create a recruiting tool for the American military is irrelevant, as that is exactly what this film has become.
Filmmaking as a medium is far from being a "pure" medium that avoids being manipulated by those of any bias to serve their ends. As such, even the filmmakers themselves do not always determine what the message they are conveying to the audience is.
Though many filmmakers try to do just that, intending to manipulate their audience towards a particular viewpoint and not always succeeding. As in the example above, through a basic examination of the story of American Sniper, one might think of it as an anti-war film, yet the reality is that it has been used to serve the exact opposite function, as a recruiting tool.