What happened was, that two opposite social systems, existing within the same political body, came into rivalry, into hostility, and at last into direct conflict. In the early stages, slavery had on its side the advantage of an established place under the law, the support of its local communities becoming more and more determined, the long-time indifference and inertia of the free States, custom, conservatism, timidity, race prejudice. But against all this were operating steadily two tremendous forces. In the race for industrial advantage which is at last the decisive test, free society was superior to slave society by as much as the freeman is superior to the slave. The advantage of the Northern farmer or mechanic over the negro slave was the measure of the advantage of the North over the South. In increase of wealth; in variety, intensity, and productiveness of social life; in immigration; in intellectual progress, the free States outstripped the slave States by leaps and bounds. And, again, in the conscience of humanity,--in mankind's sense of right and wrong, which grows ever a more potent factor in the world's affairs,--the tide was setting steadily and swiftly against slavery. To impatient reformers who, as Horace Mann said, were always in a hurry, while God never is,--the tide might seem motionless or refluent, as to him who looks hastily from the ocean shore; but as the sea follows the moon, the hearts of men were following the new risen luminary of humanity's God-given rights. And so, under each special phase of the conflict, slavery had against it that dominant force which acts on one side in the material progress of society, and on the other side in the human conscience; that force--"some call it Evolution, and others call it God." CHAPTER VIII THE MEXICAN WAR We have seen that about 1832-3 a new distinctness and prominence was given to the slavery question by various events,--the substantial victory of the South Carolina nullifiers, and the leadership thenceforth of the South by Calhoun; Nat Turner's rising, and the rejection by Virginia of the emancipation policy; the compensated liberation of the West India slaves by the British Government; and the birth of aggressive Abolitionism under the lead of Garrison. We have now to glance at the main course of history for the next twenty years. Party politics had for a time no direct relation to slavery. The new organizations of Whigs and Democrats disputed on questions of a national bank, internal improvements, and the tariff. The Presidency was easily won in 1836 by Jackson's lieutenant, Van Buren; but the commercial crash of 1837 produced a revulsion of feeling which enabled the Whigs to elect Benjamin Harrison in 1840. His early death gave the Presidency to John Tyler of Virginia, who soon alienated his party, and who was thoroughly Southern in his sympathies and policy.