Final answer:
The Dred Scott decision declared an enslaved man was not entitled to freedom after living in free states and ruled African Americans could not be U.S. citizens, causing outrage in the North and satisfaction in the South, increasing tensions that led to the Civil War.
Step-by-step explanation:
The Dred Scott case, formally known as Dred Scott v. Sandford, was a landmark decision by the U.S. Supreme Court in 1857.
The court ruled that Dred Scott, an enslaved African American man who had resided in free states, was not entitled to his freedom and that African Americans could not be considered citizens of the United States.
Furthermore, the Supreme Court decision asserted that Congress did not have the authority to prohibit slavery in the U.S. territories, which nullified the Missouri Compromise.
The reaction to the Supreme Court's ruling was profound and divisive. Many northerners and members of the newly formed Republican Party were outraged, as the decision effectively spread slavery into the western territories and struck at the core of the party's anti-slavery platform.
Southerners, particularly radical secessionists known as Fire-Eaters, were pleased with the decision as it reinforced the institution of slavery and potentially expanded it into new territories. The case heightened tensions between the North and South, contributing to the sectional strife that would lead to the Civil War.