The Kansas-Nebraska Act, passed in 1854, ended rules about where slavery could be. It let people in new areas (like Kansas and Nebraska) decide if they wanted slavery or not. This made the North and South argue more.

Douglas believed that this decision had respected the right of the American people to govern themselves. But When the act was passed，Lincoln was very angry with that. Because though The act said The local people Can decide whether their state was going to be a slavery Or not. But at the time, slavery would be better for the local economy. That means the local people must choose That their states will be a Slavery state Not liberty. And it will coursed the union to be broken.

Lincoln engaged in a series of debates and speeches with Douglas Against his Opinion. Lincoln pointed that Americans governing themselves is self- Government, but if Americans not only govern themselves but also govern the black people, then this is not self- Government, it is tyranny. And pointed out that everyone should be equal including black people, foreigners . Lincoln always used the Declaration of Independence, the foundation of the United States, as the main argument that all men are created equal .

We can discover that Lincoln What's for the. All humans are equal and liberty，And the unity of the country. But when we look at Douglas, it was so that he could become president. He just for his own Benefit，but he also presented that he was for the American people's rights.This whole affair showed Lincoln's Big vision, He can consider About all human and The Unity of whole country.