This is an interview with Professor James M. McPherson, one of the top historians of our day. It’s a pretty good interview.
When discussing why there is a large interest in the Civil War, McPherson answers, “One reason for the widespread and intense interest in the Civil War is the very reason that inspired my own interest, as outlined in the previous answer. The issues of the heritage of slavery and its abolition in a context of bitter conflict, nationalism versus regionalism, the role of government in social change, racism and anti-racism, civil rights and civil liberties, that were at the core of events in the 1860s are still relevant and contested today. Second, many of the historical figures associated with the Civil War loom larger than life in our historical consciousness, and have an endless fascination for people today. Third, the huge loss of life (now estimated to be in the range of 750,000 soldiers plus an unknown number of civilians) dwarfs anything else in American history and continues to cast a long shadow across our consciousness. Finally, military history is exceedingly popular with the public (not so much within academia), and for Americans no military history can match that of the Civil War for endless argument and second guessing.”
When asked what caused the Civil War, Professor McPherson said, “Historians today would agree almost unanimously that the slavery issue was the fundamental and ultimate cause of the war. But it is useful to break this question down into two–or even three–parts. First, there is no question but that the issue of slavery, its expansion, and its future, was the basic reason that the first seven slave states seceded in response to Lincoln’s election on a platform of containing the future expansion of slavery as a first step, in Lincoln’s words two years earlier, toward bringing about its ‘ultimate extinction.’ Every seceding state and secessionist leader made this point. Slavery had been the fundamental cause of increasing sectional polarization since the Wilmot Proviso in 1846. But secession of those seven states did not inevitably mean war, though it certainly made war a distinct possibility, even a probability. A series of decisions, actions, and non-actions by Congress, the Buchanan administration, and the incoming Lincoln administration prevented any meaningful compromise during the winter of 1860-61, and then another series of decisions by the new Confederate government and the new Lincoln administration brought the crisis at Fort Sumter to a showdown. The immediate cause of war was the Confederate decision to fire on Fort Sumter. So the bottom line is that without slavery there would have been no secession, and without secession and a Northern majority’s refusal to accept the legitimacy of secession, there would have been no war.”
The interview is, in my opinion, well worth your time.