During this time the Southern States gained a new law stating that all slaves must be returned to their owners. Dredd Scott who was a slave had been living in a free state and territory (Illinois and Wisconsin) for 10 years and said he was a free man. He sued His owner's wife after his owner died.
His owner did not deny that he was living in Illinois and Wisconsin but didn't believe Scott was a citizen of the United States. He believed Scott still belonged to his family.
The Supreme Court had to decide 3 things weather he had a standing to sue, second if blacks where entitled to rights a citizen and finally if they could restrict rights of states to decide if they would enter the union as slave or a free state. They decided Dred Scott was not a citizen and he was not a free man.
This case affected the country because it was a major event in the cross road to the Civil War. The Supreme Courts provocative ruling-blacks did not have any rights which white men should respect and rejected to ban slavery within its own borders-frustrated the public opinion in the North.