I think diplomatic and economic intervention could have solved the problems before the war began.  The States and central government mechanism were clearly incapable of doing it.  However, I do not believe the war was inevitable. In fact it resulted from serious blunder and miscalculation (not unusual causes of war) that could have been corrected easily.  The underlying causes would, admittedly taken great effort to resolve, but given the conditions of the day it could have been accomplished and 600,000 plus lives spared.

I can swear there ain't no heaven but I pray there ain't no hell. _ Blood Sweat & Tears