The legislative package known as the Compromise of 1850 postponed the Civil War by a decade. However, like the 1820 Missouri Compromise, the Compromise of 1850 failed to resolve the question of slavery in a meaningful way. Over the course of the 1850s, the inadequacies of both measures were made painfully clear. 'Popular sovereignty' undermined the Missouri compromise by suggesting the earlier division of the country along the thirty-sixth parallel into free states and slave states no longer applied. Indeed, the Kansas-Nebraska Act of 1854 permitted slavery. The resulting bloodshed in Kansas, like later incidents at Harper's Ferry, presaged the violent conflict of the Civil War."

Question

The legislative package known as the Compromise of 1850 postponed the Civil War by a decade. However, like the 1820 Missouri Compromise, the Compromise of 1850 failed to resolve the question of slavery in a meaningful way. Over the course of the 1850s, the inadequacies of both measures were made painfully clear. 'Popular sovereignty' undermined the Missouri compromise by suggesting the earlier division of the country along the thirty-sixth parallel into free states and slave states no longer applied. Indeed, the Kansas-Nebraska Act of 1854 permitted slavery. The resulting bloodshed in Kansas, like later incidents at Harper's Ferry, presaged the violent conflict of the Civil War."

—Library of Congress
Question
Use the passage to answer the question.
What does the author mean in saying that popular sovereignty "undermined the Missouri compromise”?

Answer 1

The author means that popular sovereignty, the idea that the residents of a territory should decide for themselves whether or not to allow slavery, went against the principles of the Missouri Compromise. The Missouri Compromise had established a clear line dividing free states and slave states, but popular sovereignty allowed for the possibility of slavery in areas that were supposed to be free according to the Compromise. This undermined the previous agreement and exacerbated tensions over the issue of slavery, ultimately leading to violent conflicts.