Final answer:
Resolving the issue of slavery in the western territories was complex due to its deep economic and social ties in the South, differing regional perspectives on federal authority over slavery, and the threat it posed to the balance of political power between North and South.
Step-by-step explanation:
The difficulty in resolving the issue of slavery in the western territories arose from a combination of factors. Primarily, the issue was deeply rooted in the economic and social fabric of the southern states, which relied heavily on a slave economy. Additionally, the expansion of slavery was seen as a threat to the balance of power between the northern and southern states, as a shift could potentially dominate national politics.
The federal government's authority to regulate slavery in these territories was challenged, as precedents like the Northwest Ordinance and the Missouri Compromise had set a precedent for Congressional authority. Across the country, there was a lack of consensus on how to address the issue. Northerners and abolitionists saw the spread of slavery as a moral failing and a threat to free labor, while southerners believed it was essential to their way of life.
Attempts to find a middle ground, such as the Compromise of 1850, proved largely ineffective in lessening tensions, and each new crisis, including the Fugitive Slave Act and the Dred Scott decision, only drove the wedge deeper, ultimately leading to the Civil War following Abraham Lincoln's election in 1860.