On June 19, 1862, Congress prohibited slavery in all current and future United States territories (though not in the states), and President Lincoln quickly signed the legislation. By this act, they repudiated the 1857 opinion of the Supreme Court of the United States in the "Dred Scott Case" that Congress was powerless to regulate slavery in U.S. territories. This joint action by Congress and President Lincoln also rejected the notion of popular sovereignty that had been advanced by Stephen A. Douglas as a solution to the slavery controversy, while completing the effort first legislatively proposed by Thomas Jefferson in 1784 to confine slavery within the borders of existing states.