World War One influenced American writers in a number of ways. Wartime experience compelled many writers to adopt a style of realism rather than the standard romanticism of pre-war literature. Novelists like F. Scott Fitzgerald and John Steinbeck became well known for their stark realism and simplicity. In addition, the language of American literature became much harsher. In the decade immediately following the war, a number of novels - including, most notably, Henry Miller's Tropic of Cancer, were subject to censure. Ultimately, the war had the effect of broadening the scope of what was considered acceptable in the world of American literature.
World War I influenced American writers in two distinct ways, especially those who actually experienced the war such as Ernest Hemingway, E. E. Cummings and John Dos Passos. Other writers, including F. Scott Fitzgerald and William Faulkner and several others who never actually served, also felt the effects of the war. First, writers of the period became disillusioned with American values and traditions. Some, like Hemingway and T. S. Eliot, escaped America after the war and expatriated to Europe. Second, the war helped inspire a revolution in style, including a focus on detached, fragmented writing which also portrayed life with gritty realism. Prose and poetry tended to lack ornamentation and looked to discard the techniques of the past in order to experiment with new approaches.
Even though America didn't enter the war until late, the soldiers who served witnessed firsthand the brutality and horrors of what was considered the first modern war, replete with new and terrifying weapons such as machine guns, airplanes, poison gas and tanks. Hemingway, Dos Passos and Cummings served as ambulance drivers during the war. Their postwar work often focuses on the disillusionment of the individual with American morals and institutions.
In his short story "Soldier's Home," Hemingway portrays a returning veteran who was obviously traumatized by what he saw as a Marine in some of the bloodiest of battles of the war. Harold Krebs comes home a man who no longer believes in the traditional American approach to life. He is apathetic toward work, despite the influence of his father, a banker in real estate who seems to symbolize the American belief in the Protestant work ethic. At one point, Krebs's mother tells him that his father believes "All work is honorable," noting that Harold just needs to do something. Krebs also recoils from the religious piety of his mother. When she asks him to pray with her, he simply says, "I can't," reflecting his loss of spirituality in the face of the realities he saw during the war.
Likewise, John Dos Passos overtly criticizes American institutions in his book about the war, Three Soldiers, and in his trilogy, U.S.A. In Three Soldiers, Dos Passos portrays the American military as a machine which does not care about the individual. According to the eNotes critical evaluation of the novel, Dos Passos shows the "immorality and brutality of the military machine, not toward the enemy but toward its own individual atoms, the soldiers." In U.S.A. Dos Passos criticizes America's xenophobia, isolationism and, in particular, the excesses of capitalism. In U.S.A., capitalism is inhumane and Dos Passos seems to champion the alternative systems of socialism and communism. Later, like John Steinbeck, he would alter his ideas about communism after discovering the excesses of the Soviet Union.
In his poem "next to of course god i...," E.E. Cummings treats American patriotism and nationalist zeal with humor and derision, mixing American patriotic language ("land of the pilgrims," "dawn's early") with ironic jabs at those who would blindly go off to war:
why talk of beauty what could be more beaut-
iful than these heroic happy dead
who rushed like lions to the roaring slaughter
Not only did Cummings thumb his nose at American institutions but he also abandoned traditional poetic styles with his haphazard punctuation, lack of capitalization and forays into concrete poetry. Likewise, prose writers such as Hemingway and Faulkner experimented with and mastered new styles. Hemingway disregarded established literary plot structures with his detached, almost newspaper-style narratives which often lacked expositions, transitions and resolutions. In his first set of short stories, In Our Time, he interspersed his stories with short vignettes, which were simply fragments of text which lacked introduction or explanation. These fragments seemingly portrayed the way a combat soldier might view a battle in which he is just a small part without ever realizing the broader implications of his participation. (In "Soldier's Home," Krebs needs to consult books about the war in order to understand what really happened.)
In stories such as "Hills Like White Elephants" and "Big Two-Hearted River," Hemingway abruptly places the reader in the middle of the story with nothing to introduce the characters or plot other than symbolic descriptions of the physical setting. In "Hills," the story never really identifies what the American and Jig are talking about. In "Big Two-Hearted River," Hemingway seems to tell a simple story about a man fishing, yet the story is really about a returning soldier desperately attempting to hold on to his sanity and come to grips with what has happened to him in the war.
While William Faulkner never experienced battle firsthand (he lied about having served in the Royal Flying Corps), his writing furthered the experimentation of those such as Hemingway and Cummings. His first literary triumph, The Sound and the Fury, opens with the story being described by a mentally challenged man who seems to glimpse only fragments of the world. In As I Lay Dying, he tells the story of a family carting the corpse of their dead mother across country from the viewpoint of several different characters. In each case, Faulkner employs a "stream of consciousness" technique which suggests that there are no final truths in the world. Ultimately, the truth is open to the interpretation of the individual and his unique experience and perspective. This style proved essential to Faulkner's description of the decaying south that he sought to examine in his novels and stories. It was also a good way of depicting a world that seemed to have lost its foundation and traditions in the face of modern warfare.