Your best example of a "historically efficient way to solve political problems" is a 4 year civil war that killed more than half a million people and, after all that, still left African Americans as second-class citizens for a century after?

I wonder what an inefficient way would look like.

Slavery was violence. It can't exist without considerable violence and involved violence.

So, we can say that it was violence problem that got solved by violence. Not just political problem.

by creating new problems