The most accurate statement regarding the role of the Civil War in American poets' shift from Romanticism to Realism is:
It revealed to all Americans, including poets, how destructive human passions could be.
The Civil War exposed the brutal realities of conflict, loss, and suffering, prompting poets to move away from the idealized and sentimental themes characteristic of Romanticism. Instead, they began to focus on the stark truths of human experience, emphasizing realism and a more candid portrayal of life, including its harsh realities. This shift reflected a deeper understanding of the complexities of human nature and the harsh consequences of passion and conflict.