2. The federal government's policies also encouraged the growth of slavery. The Missouri Compromise of 1820 admitted Missouri as a slave state and Maine as a free state, but it also drew a line across the country at 36°30' north latitude, above which slavery would be prohibited. This line effectively made the South a "slave zone," where slavery was protected by the federal government.
3. The Supreme Court's decision in Dred Scott v. Sandford in 1857 further strengthened slavery. The Court ruled that African Americans were not citizens of the United States and therefore could not sue in federal court. This decision made it even more difficult for slaves to challenge their status or gain their freedom.
4. The growing political power of the South also helped to protect slavery. By the 1850s, the South had become a dominant force in Congress and the presidency. This made it difficult for any political party to pass legislation that would threaten slavery.
As a result of these factors, slavery became deeply entrenched in the Southern economy and society by the early nineteenth century. It would take a bloody civil war to finally bring an end to this institution.