Slavery was so heavily contested in the early United States that when the Constitution was adopted in 1787, it was largely omitted in order to secure agreement on ratification. Northern states continued to press for abolition, while Southern states remained firmly supportive of slavery. In 1808, Congress banned the further import of slaves, but the conflict persisted. In 1819, admitting Missouri as a state triggered a national crisis because slavery already existed in the Missouri Territory. A compromise admitted Missouri as a slave state and Maine as a free state to preserve the balance between free and slave states, and it also prohibited slavery in Louisiana Purchase lands above latitude 36°30'. Northern Illinois was settled largely by people hostile to slavery, and in Freeport abolitionists included Oscar Taylor, whose home is reputed to have been a stop on the Underground Railroad, and Dexter A. Knowlton. In 1854, Knowlton and his family hosted Frederick Douglass while Stephen A. Douglas was in Freeport promoting the Kansas-Nebraska Act. Douglass attended Douglas's speech, the only time he ever heard him speak. Later, during his 1858 debate with Lincoln, Douglas tried to use Douglass's 1854 Freeport visit to stir racial division, but the Freeport audience answered with shouts of "So what?"