What statement best describes the views of the Northern and Southern leaders before the start of the Civil War?

Before the Civil War, Northern leaders largely viewed the Union as a critical entity that needed to be preserved, emphasizing free labor and opposition to the expansion of slavery. In contrast, Southern leaders championed states' rights and the preservation of slavery as essential to their agrarian economy and way of life. This fundamental clash over economic interests, governance, and social values created deep divisions that ultimately led to the outbreak of war. Both sides held firm to their beliefs, making compromise increasingly difficult.