The Kansas-Nebraska Act was a law passed by Congress in the 1850's near the time of the Compromise of 1850. It was introduced as a Bill by Senator Stephen A. Douglas as part of a bill for the construction of a transcontinental railroad whose Eastern terminus would be Chicago. In order to secure Southern votes, Douglas added language to the Bill which read "all questions pertaining to slavery in the Territory, and in the new states to be formed therefrom are to be left to the people residing therein, through their appropriate representatives." The purpose was to allow the slavery issue to be resolved locally by "popular sovereignty." It's ultimate effect was to abolish the Missouri Compromise (under which slavery would have been forbidden in Nebraska territory) and as a result inflamed the slavery issue even more. Two governments were elected in Kansas by slave and free groups. Slavery supporters from other territories crossed over to vote in Nebraska territorial elections to influence the vote. Many who opposed slavery--"free soilers"--did so not because of moral qualms because of racial prejudice. By forbidding slavery, they hoped to prohibit settlement by blacks in the territory altogether.
The dispute soon became deadly. Henry Ward Beecher, brother of Harriet Beecher Stowe, sent rifles to the free state forces. They became known as "Beecher's Bibles." After slavery supporters killed several free territory people, John Brown (of Harper's Ferry fame) attacked a slave supporting town and hacked several people to death. It was here that Brown made a name for himself as a champion for abolition. The disputes over the slavery issue led to the sobriquet, "Bleeding Kansas."
In the Pre- Civil War days of believing that compromise can solve all problems in the young nation, the Kansas- Nebraska Act was another political maneuver that sought to avoid confronting the challenging slavery question. Essentially, the act divided the Nebraska territory into territories that could decide the "free state" vs. "slave state" issue by popular sovereignty. Senator Stephen Douglas from Illinois proposed the legislation, believing that it would be better for settlers to decide the issue through their own vote as opposed to making government intervene in the issue. The result of "Bleeding Kansas," where pro- slavery and anti- slavery settlers rushed to decide the issue through armed confrontation proved the legislation to be a disastrous miscalculation on his part. In the end, the Act was another telling sign that the nation could not resolve the issue of slavery without armed conflict and that it could not be negotiated away.
The Kansas-Nebraska Act was a law passed in 1854 that did a lot to help make the Civil War more likely. It caused there to be more anger between the North and the South.
The Act said that Kansas and Nebraska would get to decide whether they wanted to have slaves or not. This went against the Missouri Compromise, which had already decided that both territories could not have slaves.
This, in itself, made the North mad. But what made things worse was the fighting in Kansas that came out of this. Pro- and anti-slavery settlers competed in Kansas to get the largest population and so win the vote over slavery. This competition included lots of violence.
Kansas-Nebraska Act of 1854 repealed the Missouri Compromise of 1820. It applied the principle of popular sovereignty to the territories. It permitted the expansion of slavery beyond the Southern states. It also sparked the formation of the Republican party.