The outcome of the American Civil War (1861-1865) significantly altered the institution of slavery in the United States. The Union's victory led to the passage of the 13th Amendment, which abolished slavery in the country. This monumental change marked the end of legal slavery and prompted necessary social and political transformations. However, the reconstruction period that followed faced challenges, as many Southern states enacted discriminatory laws to undermine the advancement of formerly enslaved people. The war and its aftermath laid the groundwork for the ongoing struggle for civil rights and social justice in the United States.