Final answer:
The North fought to preserve the Union and later to abolish slavery, whereas the South fought to maintain slavery and uphold their right to self-governance. Economic, social, and political differences between the two regions underpinned their contrasting reasons for engaging in the Civil War.
Step-by-step explanation:
The reasons that the North and South had for fighting in the Civil War were fundamentally different and rooted in their respective economic, political, and social systems. The South fought to preserve slavery as it was integral to their agricultural economy which relied on slave labor for producing cash crops like cotton and tobacco. Conversely, the North was not as dependent on slavery economically and fought primarily to preserve the Union and maintain the nation as a single entity. While Lincoln's stance on slavery did evolve to include abolition, he initially took up arms to keep the United States together. The conflict also represented differing views on states' rights with the South advocating for more localized control, especially over the institution of slavery, while the North supported centralized control over crucial issues. Fundamentally, both sides saw themselves as fighting for liberty and their interpretation of the American Revolution's legacy, though their definitions of 'liberty' diverged significantly.
In summary, Northern perspectives were driven by the desire to maintain the Union and, later in the war, to end slavery, while Southern perspectives were dominated by the desire to maintain the institution of slavery and the right to self-govern through a confederation of states.