The Southern leaders, therefore, wanted free trade with England; the North urged protection, in the interest of the whole country, rather than a group of States. The South believed that Northern politics was selfish; the North believed that the Southern leaders were building up English manufacturers, and weakening their own country! The people became one great debating club, and the dispute waxed more bitter day by day. Every new event seemed to widen the breach. The war of the Revolution made for unity between North and South, just as the hammer welds together two pieces of red hot iron. The soldiers of the Revolution had marched under the same flag, supported the same Declaration of Independence, and fought for the same Constitution. Slavery in the North had died through inanition, and during the eighteenth century in the South also slavery seemed in process of extinction. But now, in 1830, slavery had become a great source of immeasurable wealth to the South, just as manufacturing had built up the prosperity of the North. The tariff discussion came to a climax in 1828, through the passing of a customs act, known as the Tariff of Abominations. Sparks falling on ice carry no peril, but sparks falling on the dry prairie cause conflagrations. The news of the passing of the protective tariff created intense excitement in South Carolina. Public meetings were called in all the towns in the land, and protests were made against the execution of the new law. Legislators in the State capital, orators on the platform, editors through their columns, urged nullification. There were two reasons for this growing hostility to protection on the part of the citizens of Calhoun's State; first the belief that as England was the largest purchaser of cotton, it was to South Carolina's best interest to have English goods brought in free; second the conviction that the tariff was a strictly sectional movement in the interest of the manufacturing North, as opposed to the South with her raw cotton and slave labour. As a candidate for the vice-presidency in 1828 on the same ticket as General Jackson, Calhoun took no definite step until after the election, when he published a paper showing the evil which the protective tariff was doing the Southern states, and asserting the right to interpose a veto. In January, 1830, having broken with Jackson and abandoned all hope of later obtaining the presidency by his aid, Calhoun decided to test the theory of nullification upon the national theatre. Accordingly, under his direction, Senator Hayne inserted in his speech on the Foote Resolution on the public lands the defense of what was to be known later as the South Carolina Doctrine,--that, if a State considered a law of Congress unconstitutional (as South Carolina asserted the recent tariff act to be) the State had the right to nullify the law, and, if obedience was sought to be enforced, the right to secede from the Union.