Marshall Nunn states that "For Ruben, [Roosevelt] is the representative man of the United States...[and the poem details] The imperialistic attitude that Roosevelt took regarding the building of the Panama Canal"
Here, Roosevelt is not only literally the leader of the United States, but also represents the same ideals the United States was founded on. Throughout the poem Dario no longer addresses Roosevelt, but rather addresses the United States as a whole. With the assumption that Roosevelt represents the greater collective beliefs of the United States.