The Dred Scott decision struck a blow to those who believed Congress could legislate the bounds of slavery. The Supreme Court's ruling effectively said slavery could move into new territories and even be tolerated in the free states of the North. Since Dred Scott was a slave who had spent significant time in a free state, the Supreme Court, by upholding his enslavement, effectively blurred the geographical lines between freedom and slavery. This essentially eradicated most of the provisions laid out in the Missouri Compromise.
Furthermore, the Supreme Court affirmed the lack of rights of slaves. The court's official ruling was based on their decision that Dred Scott himself had no right to bring the suit against his slave master. As a slave, he lacked the rights of a citizen, they argued. The justices in majority argued that Dred Scott should never have been able to sue for his freedom in the first place. This decision further cemented the lack of rights slaves had.
Beyond the immediate decision of the Supreme Court, the Dred Scott decision further exacerbated the unrest in the country between abolitionists and supporters of slavery. Many northerners, including many in Congress, were outraged by the decision. Charles Sumner, a congressman from Massachusetts and ardent abolitionist, said long after the decision
I speak what cannot be denied when I declare that the opinion of the Chief Justice in the case of Dred Scott was more thoroughly abominable than anything of the kind in the history of courts. Judicial baseness reached its lowest point on that occasion.
Southern supporters of slavery counted the Dred Scott decision as a major victory. The court's ruling set the precedent that slavery was permissible in all parts of the United States, regardless of the Missouri Compromise.
The animosity brought about by the Dred Scott decision likely brought the United States one step closer to civil war. The reaction of both sides made it clear to their opponents that the issue of slavery could not be settled by the government, but only through the dedicated and determined effort of each opposing side.