Vladimir Lenin's "A Letter to American Workingmen" was an attempt to explain the logic behind the peace with Germany negotiated by the newly formed revolutionary government of Russia. This peace was strongly condemned by many western governments.
Lenin begins by talking about his admiration for both the American Revolution and the Civil War, emphasizing how much they differed from imperialistic conflicts. He draws a distinction between armed conflicts that further the cause of justice and those that simply enrich one group of wealthy elites at the expense of other wealthy elites. He suggests that workers should not support such imperialistic wars. For example, he argues that no matter how British imperialists and German imperialists divide up Africa, both are imperialists, and their colonial acquisitions are not only unjust, but only benefit the wealthy elites in their home countries.
He concludes that a socialist government like that of Russia is by its nature neutral in such conflicts, as neither side in World War I represented the interests of workers.