Lincoln's assassination
Whitman writes about Lincoln's assassination a half decade after the event. He reports to the reader that the assassination was designed to incite more violence or disparity, but actually, the event had the inverse effect, actually leading to a readiness to be at peace. The unity and stability of the nation in the aftermath of Lincoln's death is evidence of history's trajectory, he writes, but still, Whitman cannot help but take a cynical approach to issues. He sees the peace time as a kind of buffer between one kind of conflict and another.
Neighborly relations
The evidence for Whitman's pessimism is derived from his experience of his neighbors. He realizes that over the course of his life, the public opinion about what it means to be a neighbor has changed. Instead of heart-warming pictures of community, neighbors seem basically to be competing with each other. Instead of sharing and supporting one another, each home has become a community unto itself with tribal walls of loyalty between them and their neighbor. Whitman says such living can only breed negative results, like paranoia and anxiety.
Capitalism and democracy
Plus, there is the systemic issue of capitalism and hyper-individualization. What becomes of the democracy when people take such a competitive, isolating point of view of life? When everyone is just out to make a buck, then what happens? The answer is imbalances as people become wealthy and warp the shape of the nation's government. Whitman is concerned that the nation's zeitgeist is leaning too far toward profit and not enough toward the public good.
Frontier ideology
The frontier ideology is used as synecdoche for the nation's unhealthy appetite for more. Whitman sees that whole Louisiana Purchase conundrum as perfect evidence. In that case, Jackson's presidency radically altered the fate of the fledgling nation, pointing westward for more and more economic growth. Eventually this association with money and the unknown West is an uncanny metaphor for how capitalism operates. The frontier is treated romantically by those with desires for power or money.
Nature and technological
There is a symbolic relationship between nature and technology in this book. Whitman is famously pro-nature both physically and meta-physically. He is conscious of nature and the way that human behavior interacts with nature—that is the subject of much of his poetry. Therefore, he quickly notices that technology tends to have an exponential way of changing nature, often damaging nature in serious or permanent ways. He says that he is concerned that America will abandon her obligation to nature.
