How did Copland's work reflect American themes through its musical structure?

Copland’s work exemplifies American themes through its expansive harmonies and thematic materials, which are closely associated with the ideas of openness and vastness often linked to the American landscape. His music frequently incorporates wide intervals and sweeping melodic lines that evoke the grandeur and spirit of America, reflecting its diverse cultural heritage and ideals such as freedom and democracy.

Additionally, Copland made use of folk elements and simple, accessible melodies that connect to American roots, illustrating the common man's experiences and sentiments. Such characteristics serve to evoke a sense of place and identity, allowing the music to resonate with listeners on a personal level, giving it a distinctly American character.

In contrast, mirroring European classical traditions would limit the individuality of the music, while minimalist compositions often emphasize repetitive structures rather than expansive themes. Focusing on dissonant soundscapes would create tension and unease, which is not characteristic of the predominantly optimistic and open qualities found in Copland's works. Thus, the use of expansive harmonies and thematic materials effectively embodies the essence of American themes in his compositions.