I must respectfully disagree with the term "War of Northern Aggression". However, The Freedmans bureau was a great idea and had some success. But it failed because of Johnson's policies. It was not the war aim of the north to free the slaves at first - it was to preserve the union. So you may be correct that slavery would have ended on its own without war. In that case, it should have been the southern states who realized that fact more than anyone and should have chosen not to secede to protect that "peculiar institution".............