How did the Dred Scott decision affect laws that limited slavery in U.S. territories?

The Dred Scott decision of 1857 fundamentally altered the legal landscape regarding slavery in U.S. territories by declaring that Congress lacked the constitutional authority to prohibit or abolish it.123

By ruling that the Missouri Compromise was unconstitutional, the Supreme Court effectively invalidated the primary legal mechanism that had limited the expansion of slavery into federal territories for nearly four decades. Chief Justice Roger B. Taney’s opinion asserted that the federal government had no power to restrict slavery in these regions, thereby stripping the "free soil" movement of its constitutional legitimacy. Furthermore, the decision rejected the doctrine of popular sovereignty, as articulated in the Kansas-Nebraska Act, by suggesting that even the people of a territory could not legally exclude slavery.123

By effectively opening all U.S. territories to slavery, the ruling outraged the North, intensified sectional polarization, and served as a critical catalyst that pushed the nation toward the American Civil War.412