If Lincoln had Honored the Constitution ...

We would live in a drastically different world.

Absent a bloody Civil War, the USA and CSA would likely have forged both economic and political ties and jointly continued something like the Monroe Doctrine.

European history for the next fifty years would likely not have been much different. Something like the Great War would likely have happened. The result would have been very different. When both sides quit from exhaustion absent US intervention, there would have been no Treaty of Versailles, no humiliation of Germany and thus no Hitler.

So basically, Lincoln killed 6 million Jews.