But in all these thirty years the subject of slavery had little prominence in public discussion. Now it suddenly came to the front. A bill was brought into Congress to permit Missouri to organize as a State. It was part of the Louisiana purchase, of which the Southern portion had inherited and retained slavery; but Missouri was geographically an extension of the region of the Ohio States, in which free labor had made an established and congenial home. It was moved in Congress that slavery should be excluded from the new State, and on this instantly sprang up a fiery debate. On one side it was urged that slavery was a wrong and an evil, and that Congress had full power to exclude it from a State as a condition of admittance to the Union. On the other side slavery was defended not only as an industrial advantage, but as morally right and a benefit to both blacks and whites. It was strenuously declared that the people of each incoming State had a right to determine their own institutions; and it was also urged that to keep the balance of power between the two sections, it was necessary that slave States should be admitted equally with free. It was disclosed with startling suddenness that two systems of labor and society stood face to face, with different ideals, different interests, and in a mutual opposition to which no limits could be foreseen. It was plain that with the increase of profit from slavery all idea of its abolition had been quietly dropping from the minds of the great mass of the Southern community. It was equally plain that the sentiment against slavery in the North had increased greatly in distinctness and intensity. There was apparent, too, a divergence of material interests, and a keen rivalry of political interests. The South had been losing ground in comparison. From an equality in population, the North had gained a majority of 600,000 in a total of 10,000,000. The approaching census of 1820 would give the North a preponderance of thirty in the House. In wealth, too, the North had been obviously drawing ahead. Only in the Senate did the South retain an equality of power, and, to maintain at least this, by the accession of new slave States, was an avowed object of Southern politicians.