The ultimate weakness of the doughfaces, from a Southern perspective, came over the issue of popular sovereignty. At the time of the Kansas-Nebraska Act, popular sovereignty was accepted by both the northern and southern Democrats as the proper states' rights position. It protected against federal consolidation and insured the equality of the states to compete in the territories. Douglas and many northern Democrats remained consistent through 1860 in their support for popular sovereignty. Southerners, on the other hand, saw the increasing strength of the anti-slavery movement in the North and by the late 1850s were no longer content simply to rely on preventing the Federal government from interfering in the territories. They now insisted on Federal intervention to protect slavery in the territories and prevent any decision on slavery until a territory prepared a constitution as part of an application for statehood. Northern Democrats such as Douglas could not go that far with the South. The doughface, as an agent for sectional compromise, had outlived his usefulness.