World War II required sacrifices greater than any the American people had been forced to bear since the American Civil War. Maintaining morale at home was therefore a crucial war aim. To do so, the United States government unleashed a flurry of propaganda aimed at reminding Americans that the cause they were sacrificing for was a noble one, and perhaps even more important, individual action, no matter how seemingly insignificant, could make a difference in the war effort.
The Office of War Information was formed at the outset of the war to ensure that this message was seen as much as possible. Drivers on the nation's highways saw billboards reminding them to carpool, some posters telling them that onerous wartime rationing was absolutely essential, and others designed to encourage enlistment.
The motion picture industry in the United States was quickly enlisted in the war effort. Various moviemakers formed the Motion Picture Committee Cooperating for National Defense to make national defense films, and throughout the war, the motion picture industry cranked out films with war themes that emphasized heroism and valor. Even films that were not explicitly warlike were usually preceded by newsreels which told the story of the war effort, and even short cartoons starring Donald Duck or Bugs Bunny that were designed to lift morale.
One function of propaganda was to stir up hatred of the Japanese, who were inevitably portrayed, even in cartoons, as inhuman and fundamentally evil. Germans, on the other hand were often portrayed as the victims of Adolf Hitler.
Another less insidious practice was the use of war correspondents who followed military units into combat and described the scenes they saw in heroic but often grittily realistic terms. Ernie Pyle was perhaps the most famous of these war journalists, who were mostly employed by the military itself.