Final answer:
The Civil War was influenced by the complex issues of state sovereignty, economic disparities, and the moral debates surrounding slavery. Extremist views became mainstream as the nation faced irreconcilable differences over these issues, leading to an inevitable conflict.
Step-by-step explanation:
The causes of the Civil War were complex and multifaceted. While soldiers fought for cause and comrades, and to preserve liberty and freedom in a democratic nation, underlying factors such as the fate of slavery and economic differences between the North and South fueled the conflict. Northerners believed in a 'slave power conspiracy' and felt the need to preserve the Union as well as halt the expansion of slavery. Southerners viewed the abolitionist movement as a direct threat to their way of life and the economic system of slavery that supported it. People on both sides increasingly felt the need to defend their position on slavery—it was not solely out of moral concern but also because they perceived their political and economic liberties as being at stake. The concept of an irrepressible conflict introduced by William H. Seward suggested an inevitable choice to be all slave or all free, which raised tensions further. As the war dragged on, the North and South experienced internal divisions, with the North facing draft riots and the South dealing with tensions between planters and yeomen. This culminated in the North's triumph and significant social, political, and economic changes post-war. The transformation of extremist positions into mainstream beliefs was due to increasingly polarized political rhetoric and mounting tensions, particularly over the divisive issue of slavery.