How the emancipation proclamation was a game changer for the civil war. include how it affected the goal of civil war, the combatants and how it influenced foreign nations decision as to whether or not to support one side over the other in the war How were slaves treated? what were the underlying factors for the continuation of slavery? How did slaves influence Americans economy during the time of slavery? Do you think America would have prospered into one of the most powerful countries had it not been for the economic prosperity of slavery? Explain why or why not. what was the significance of president Lincoln's Election?