Why did violence occur and Kansas after the passage of the Kansas Nebraska act

US history, nice.

So Stephan Douglas created an Act that Kansas should be split into two parts. Kansas and Nebraska and each state could decide if they want slavery or not. This basically violated the Missouri Compromise, since it calls for the states above 36'30 free of slavery and below that a slave state. And this Compromise was the one that stalled the issue of sectionalism for a while. And so for two years, violence broke out in Kansas over slavery led by abolitionist John Brown. As a result, a tension between the North and South hit high, with no chance working out.