Final answer:
The critical problem that led to the Civil War was slavery, intertwined with economic differences and concerns about states' rights and political power. Slavery's importance to the Southern economy and diverging perspectives between the North and South following the election of Abraham Lincoln escalated into conflict.
Step-by-step explanation:
One Problem Leading to the Civil War
One significant problem that led to the war between the Northern and Southern states was slavery. The subject of slavery was deeply linked to several factors that contributed to the conflict, such as economic differences, political differences, and issues regarding states' rights.
Though slavery was a moral issue that did contribute to the divide, it was also a critical part of the Southern economy, deeply integrated into their agricultural system. In contrast, the Northern states, which derived less economic benefit from slavery, had different economic structures, which created a rift when juxtaposed with the Southern dependency on slave labor.
As the nation expanded, arguments over slavery and its place in new territories and states intensified. The election of the abolitionist-leaning Republican Abraham Lincoln in 1860 exacerbated this division, prompting Southern states to secede, fearing the loss of their way of life, and eventually leading to the Civil War.