Final answer:
The main goal of the US government agency that created war posters during World War I was to increase public support for the war.
Step-by-step explanation:
The main goal of the US government agency that created war posters during World War I was to increase public support for the war. These war posters were used as a propaganda tool to sway public opinion and encourage patriotism. They were designed to evoke strong emotions and rally support for the war effort.
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