Congress passed the Kansas-Nebraska Act, which overturned the Missouri Compromise. This opened Kansas and Nebraska to white settlement and allowed popular sovereignty to determine slave- or free-state status in territories seeking statehood. The act destroyed the Whig Party, divided the Democratic Party, and prompted the creation the Republican Party. The author of this legislation was Senator Stephen A. Douglas, who had pushed the Compromise of 1850 through Congress. As chairman of the Senate Committee on Territories, Douglas had proposed that the area west of Iowa and Missouri—which had been set aside as a permanent Indian reservation—be opened to white settlement. Southern members of Congress demanded that Douglas add a clause that specifically repealed the Missouri Compromise. Instead, the status of slavery in the region was decided by a vote of the region’s settlers. In its final form, Douglas’s bill created two territories (Kansas and Nebraska) and declared the Missouri Compromise “inoperative and void.”