Final answer:
The expansion of civil rights for African Americans was the most significant consequence of the Civil War, reflected in constitutional amendments and a societal shift, despite ongoing struggles for racial equality. Additionally, the war strengthened the federal government and shifted the economic balance towards Northern industrialization.
Step-by-step explanation:
The most significant consequence of the outcome of the Civil War was the expansion of civil rights for African Americans. Legislation such as the Thirteenth, Fourteenth, and Fifteenth Amendments to the Constitution abolished slavery, granted citizenship, and protected voting rights, respectively. This period marked a monumental shift in American society, changing the legal and social status of African Americans, although the full realization of these rights would take much longer to achieve due to continued resistance and segregationist policies in the South. In addition, the war resulted in a stronger federal government which diminished the ideology of states' rights that had been a contention point prior to and during the war. The economic landscape was also altered, with the South's plantation-based economy being decimated and the North's industrial economy strengthened, paving the way for a period of significant industrialization and economic growth in the United States.