In "The Guns of August," Barbara W. Tuchman highlights how the United States evolved into a crucial supporter of the Allied powers during World War I. This transformation allowed the U.S. to function as both an arsenal and financial bank for its allies, ensuring they had the necessary resources to sustain their war efforts. This role brought about a significant change in American foreign policy and interests as the country became invested in the outcome of the war.

The direct stake that the U.S. acquired in securing an Allied victory surprised many post-war analysts who focused solely on economic factors. Tuchman's observation emphasizes that the motivations and interests of the United States during this period were more complex than merely economic determinism. The involvement in the war not only shaped the immediate outcomes but also influenced the future role of the U.S. on the global stage.