pcr makes many good points in this essay that few will be familiar with though i differ in a small amount in that as the war progressed there was a growing focus on slaves that was a lesser cause of the war in the beginning;

Paul Craig Roberts
Today (Nov. 9) I heard a black historian on NPR say that the “civil war” was fought in order to establish a framework for human rights.
He also said that black civil rights achieved by the war were overturned by the rollback of Reconstruction, put back in place by the 1964 Civil Rights Act, and was now being overturned again by Trump’s response to the caravan from Honduras.
As best as I could tell, this was an Identity Politics explanation of history with all of its contradictions and factual errors.
Identity Politics is based on the accusation that the white male is a racist and a misogynist. This is inconsistent with the belief that Washington, totally in the hands of white males, chose to fight a bloody civil war in order to bring human rights to black slaves. If white males are this idealistic and willing to make such a sacrifice for blacks, how is it that the white males are racists?
The black historian can’t have it both ways.
Moreover, how would the black historian explain how it possibly can be that the same Union army that fought to bring human rights to black slaves immediately on war’s end was sent under the same generals, Sherman and Sheridan, to slaughter the Plains Indians. Why did the Union army fight for human rights for blacks and against human rights for native American Indians?........https://www.paulcraigroberts.org/2018/11/09/the-prevalence-of-myth-over-history/