Lincoln's goals were to differentiate himself from Douglas — the incumbent — and to voice a prophecy publicly. Douglas had long advocated popular sovereignty, under which the settlers in each new territory would decide their own status as a slave or free state; he had repeatedly asserted that the proper application of popular sovereignty would prevent slavery-induced conflict and would allow Northern and Southern states to resume their peaceful coexistence. Lincoln, however, responded that the "Dred Scott" decision had closed the door on Douglas's preferred option, leaving the Union with only two remaining outcomes: the country would inevitably become either all slave or all free. Now that the North and the South had come to hold distinct opinions in the question of slavery, and now the issue had come to permeate every other political question, the Union would soon no longer be able to function.