Final answer:
The Dred Scott v. Sandford decision declared African Americans could not be U.S. citizens and denied Congress the power to regulate slavery in the territories, deepening the divide between North and South and contributing to the onset of the Civil War.
Step-by-step explanation:
The Impact of the Dred Scott v. Sandford Decision
The Dred Scott v. Sandford decision made by the Supreme Court in 1857 had profound consequences for the United States. The ruling declared that African Americans, whether free or enslaved, could not be considered citizens of the United States and therefore had no right to sue in federal court. This effectively made the Missouri Compromise unconstitutional and stripped Congress of the power to regulate slavery in the newly acquired territories.
The decision exacerbated sectional tensions between the North and South. It infuriated Republicans by making their platform of preventing the spread of slavery into the territories unconstitutional. The Democratic Party saw divisions over the Dred Scott case and the related Freeport Doctrine, ultimately affecting future political control. The decision affirmed Southern perspectives by securing slavery and provided a serious setback for abolitionist movements in the North.
In the aftermath, debates such as those between Abraham Lincoln and Stephen Douglas highlighted the growing national division on the issue of slavery. The infamous Dred Scott Decision accelerated the nation's trajectory towards the Civil War, fundamentally altering the political and social landscape of the era.