re: If the South had not fired the first shot at Ft Sumter, what would have likely happened?

On the Cotton end, England was solidifying its mercantile system. As such cotton from inside the empire became more wanted than cotton from America. The British started building cotton mills in the 1850's wholesale.

Plus there was a sentiment in Britain against dealing with a country actively trying to preserve slavery as Britain had resolved their issue 25 years earlier peacefully and through popular sentiment.

Southern planters and their politicians - usually one in the same saw their power waning vs the power in the North that was growing along with the Irish and continued influx of German immigrants coming into the country. Northern land brokers and politicians saw an advantage in enticing people to locate to newer territories and land in places like Iowa, Missouri and Easter Kansas. The Southern Planters hated it. Too many independent farmers in New rerritories limited their influence if they could get in there. Plus with the Compromise that had been in place had been breaking down because of CA and Oregon as well as Minnesota and Kansas. The North was beginning to sense that any advantage they still had could evaporate by the next election. The South had no choice but to initiate a potential separation.

The South knew that Lincoln, or for that matter, any other Northern politician other than maybe Fernando Wood was going to go along with secession for very long, if at all.The South had to start something to make their statement. Sumter was the best target....and both sides knew it, and both sides were equal provacateurs in the incident. So don't portray the Southern politicians and planters as some sort of victim.

Southern politicians brought destruction on themselves and happily would use the poorer dirt farmers as their proxies initially, telling them that this was all about their rights....although they could never explain really how any rights were being destroyed, other than the planters had been prevented from moving slavery to Western territories and New states