I get the feeling after Dred Scott and the Fugitive Slave Act that war was indeed inevitable. The North feared that the South, with the Supreme Court leading the way, wanted to legalize slavery nationwide. The South feared that the North wanted ultimately to abolish slavery nationwide. And with all that land to the West eventually reaching statehood, the North could someday have the votes to do it.
Maybe Eli Whitney made the Civil War inevitable. Most people attribute it to his invention of the cotton gin, that gave new life to the Peculiar Institution. But it was also the development of interchangeable parts, which made possible the assembly line and accelerated the industrial revolution that had already begun in the north.
Clearly, by this time, the United States was already two distinctly different societies. But yes, Dred Scott made the war inevitable.
Americans don’t usually resort to violence to resolve civil and political disputes. We go to Court. The Supreme Court isn’t perfect at resolving these differences but it’s normally pretty good. Dred Scott was the one time it failed, but maybe it had no chance of success. Even so, the decision was so bad it took a civil war and three amendments to the Constitution to undo it.