He would have spent the rest of his presidency trying to undo the damage to the powers of the states, and re-enshrined into our civics the way that rights start with the individual, then form the rights of the locality, then the rights of the state, and then from there the rights of the federal government.

It's almost like Slavery was clung to in order to force a war to erode that system, and then Lincoln was murdered not BEFORE he could end slavery, but before he could repair the world's only free nation.