Posters have long been considered an obvious vehicle to spread ideas, arguments, or allegations and to promote causes. These posters that intend to sway public opinion and spread propaganda must communicate strongly and effectively. They must speak from a position of authority, and aim to unite us in a common cause.
Since World War I, such posters have been used to motivate us by appealing to our sense of patriotism or to our darker emotions of anger at the human cost of war. The effectiveness arises from a complex layering of words, symbols, systems, and design. Sometimes just one word can get the message across by building on a broadly shared social imperative. In both world wars, "Enlist" came as a command that was often the poster's message and purpose. Such shorthand requires an easily shared idiom, as in the famous slogan "I Want You for U.S. Army."
This small selection from the enormous category of war-related posters runs the gamut from exhortations to the home front to antiwar dissent.