President Abraham Lincoln was a pioneer in many regards and the thing he’s most famous for was being the president that ended slavery.
It obviously wasn’t an easy road. Lincoln himself had to fight hard to free the many black slaves being held in the United States, be it resistance by the Democrats in Washington D.C. or the southern states which had risen up in civil war. A lot of blood was spilled before it was all over, including Lincoln’s in the end.
Like any good person trying to change the world, Lincoln had to put forth many arguments in favor of his position and debunk many other ideas to boot.