Dreiser's An American Tragedy is a commentary on success and the American social structure. Clyde is a psychotic, reckless person who feels entitled to many things which he could attain if he were smart and ambitious, but he is neither. He blames his parents for raising him in a religious environment which he resented instead of providing a wealthy upbringing for him. As he grows older, he makes increasingly irresponsible, even evil, choices for which he accepts no responsibility within himself. Ultimately, he kills the girl whom he got pregnant, Roberta, and is executed for his crime.
If Clyde had been born to a different family, he would have almost definitely ended up with a similar fate. He, however, is convinced that because of the circumstances he was born into, he would never be allowed to fulfill his full potential. In actuality, it's his complete lack of ambition and aversion to responsibility which hinder his coveted success. Dreiser paints Clyde as a delusional fool who believes he is a product of circumstance. On the other hand, Roberta is legitimately portrayed as underprivileged and predestined according to her heritage. She is a farmer's daughter, just as her father was a farmer's son. According to her lineage, she is expected to be exactly what her father was, no more, no less. She accepts this realistic outlook and does her best to fulfill her destiny.
What Dreiser does throughout the novel is raise the age-old question of whether society is justified in viewing people as products of their environments; is nature or nurture the deciding factor in a person's life? American social expectations tend to excuse a person's lack of success because of their upbringing. How could they be something different than what their ancestors were? It's as if America has accepted a system of social caste which governs its citizens' thoughts of one another but remains unspoken. Roberta certainly accepts this viewpoint, but Clyde thinks otherwise. In the end, he is the only one responsible for his awful fate, but he firmly believed otherwise. Readers are left to either condemn or clear Clyde in their own minds.
