Name one major consequence of the American Civil War.

One major consequence of the American Civil War was the abolition of slavery through the 13th Amendment. This amendment, ratified in December 1865, formally abolished slavery throughout the United States, marking a significant turning point in American history. The end of slavery not only transformed the social structure of the nation but also laid the groundwork for the civil rights movements that would follow. By eliminating the legal institution of slavery, the 13th Amendment aimed to ensure that the freedoms and rights promised by the Constitution were extended to African Americans, fundamentally changing the course of American society.

While the other choices reflect important moments and issues related to the aftermath of the Civil War, they do not represent direct consequences of the war itself at the level of legal transformation achieved by the 13th Amendment. For example, the expansion of slavery into new territories was a pre-war issue that contributed to tensions but was resolved by the war. Similarly, the end of Reconstruction and the establishment of Jim Crow laws occurred later, as responses to the changes brought about by the war and the abolition of slavery, but they do not capture the immediate consequence of the war itself.