I don’t think killing 600,000 Americans were in Lincoln’s plan. Unfortunately it, and its attendant destruction, turned out to be the cost of preserving the union. I know we have a lot of confederates on FR but I grieve for both sides.
It just happened to be that the nation was finally ready to fight over the issue. The southern rabble started bloody hostilities by raising treasonous armies and finally attacking Ft. Sumter. And the traitorous leaders ordered it in order to preserve the barbaric notion that some people could own other people - completely antithetical to the founding spirit; clearly those people were not Americans. It was high time that the barbaric notion was choked out of existence, and many of the (more educated) people knew it.
Our American shame is that it took so long for a people of good conscience to permit such a disgustingly evil system to exist as long as it did.
And also a pure wonder and bloody effort, with God's help, that the people managed to fling it off.