The sociocultural situation in the United States of America, which was not disturbed by the communist ideology of the Soviet Union against Nazi Germany during the Great Depression after World War I and World War II, was a direct determinant of Aaron Copland’s career. In this context, the composer succeeded in creating American melodies in the norms of international art music and also in a way to arouse the interest of the middle generation of the period. On the other hand, like many intellectuals of the period, he was also affected by the paranoia of communism that emerged in America after World War II and penetrated the very bones of the state. In this period, the two opposite periods of the composer’s life, who turned towards serialism, which he initially opposed, are one of the most important turning points of international art music, that is, classical music in America. This article, compiled from the publications of Crist, De Lapp and Birket, briefly touches upon these two contrasting periods of the composer’s life.