The Kansas–Nebraska Act of 1854 made the territories of Kansas and Nebraska, allowing the states to vote on whether slavery was legal or not. This law cancelled the Missouri Compromise, which declared that slavery was not legal in those areas. It was passed on May 30, 1854. The Kansas-Nebraska Act angered many in the North who considered the Missouri Compromise to be a long-standing agreement. In the pro-slavery South it was strongly supported. After the Kansas-Nebraska Act was passed, pro-slavery and anti-slavery supporters rushed in to settle Kansas to affect the outcome of the first election held there after the law went into effect. Pro-slavery settlers carried the election but were charged with fraud by anti-slavery settlers, and the results were not accepted by them. This made the population skyrocket, and also caused Kansas to gain the nickname "Bloody Kansas" because people were constantly fighting over this issue. 