I believe it was not possible to avoid the civil war. If it was avoidable, the north and south would have split into two different countries. Since the two are right next to each other, there would have been constant clashes and disagreements. The southern white would have not cooperate with the north to negotiate giving any slaves rights. As I said, war could have been pushed aside, back ultimately come back as the heat between the north and south would be much greater, creating a much more bloodier of a war than it was originally.
It never really failed but he did create a period which some refer to as the imperial presidency due to his desire to rule like a king. It pretty much was the first time that a president was using all of his powers listed in the constitution. Hope this helps:)
