Take it from Lincoln himself, who in his letter to Horace Greeley said, his "paramount object in this struggle is to save the Union, and is not either to save or to destroy slavery".
An easier way to think of it is this. If the war could have ended before the emancipation proclamation was issued if the union was preserved. If the issue of slavery was somehow solved without preserving the union, the war would have continued.
What led to the outbreak of the bloodiest conflict in the history of North America? A common explanation is that the Civil War was fought over the moral issue of slavery. In fact, it was the economics of slavery and political control of that system that was central to the conflict.
What are the three main causes of the Civil War?
What were the four main causes of the Civil War? The biggest cause of the Civil War was the humanitarian and economic issue of slavery. However, the four biggest factors of causation were slavery, states vs federal rights, economics, and the election of Abraham Lincoln in 1860.
Did slavery cause the Civil War?
Today, most professional historians agree with Stephens that slavery and the status of African Americans were at the heart of the crisis that plunged the U.S. into a civil war from 1861 to 1865.