The First World War (1914–1918) defined the “American century,” establishing global political and economic hegemony and shaping national culture and society. However, over a century after the outbreak of the conflict that served to delineate and establish the modern era within the United States, the war appears to be absent from social and collective memory. Indeed, such is the apparent neglect of the war within schemes of remembrance that the campaign for the National World War I Memorial in Washington, DC, which was begun in earnest in 2008, was based upon the sense of amnesia that obscures the role of the United States in the conflict. The reason for this absence may be regarded as due to the all-encompassing nature of the Second World War and the relatively short period in which the nation was involved in the conflict. However, such presumptions have been roundly dismissed by scholars who have demonstrated the highly important role of the United States in ensuring victory for the Entente. This work has revealed the way in which the war altered society and politics after the entry of the nation into the global conflagration. It is during this war that the forces of capitalism and immigration that had built the United States during the nineteenth century were harnessed for the war effort, monitored by the state and controlled by the government for the purposes of national security. The impact of this wartime alteration was so extensive that the process of forgetting the conflict has been highlighted by some studies as a necessary response to the repressive intrusion into the lives of civilians. It is through these accounts that a new account of the First World War and the United States has emerged which reasserts the significance of the conflict for the nation.