The events of the year 1847 had persuaded the Whig leaders that, if they persisted in the policy embodied in the Wilmot Proviso, they would surrender all power to control the ensuing Presidential election. By clever management and the avoidance of issues which involved the slavery question, they felt reasonably sure of the votes of Delaware, Maryland, North Carolina, Kentucky, and Tennessee, with a probability of securing Georgia, Louisiana, and Florida. To throw these States away by an anti-slavery crusade was to accept inevitable defeat, and disband the Whig party. Mr. Winthrop was therefore representing the prevailing wishes of Northern Whigs when he used his influence to restrain rather than promote the development of the anti-slavery policy which had been initiated with such vigor. The result of this change was soon visible. In the preceding House, with a large Democratic majority, the Wilmot Proviso had been adopted. In the Whig House, over which Mr. Winthrop presided, it was found impossible to repeat the vote during the preparations for the national contest then impending. The treaty of Guadalupe Hidalgo, by which we acquired a vast territory from Mexico, was ratified by the Senate, and the House voted the fifteen millions demanded by it without adding a restriction of any kind on the subject of slavery. Every acre of the nine hundred thousand square miles was free territory while under the rule of Mexico, and the Commissioners of that government were extremely anxious that the United States should give a guaranty that its character in this respect should not be changed. They urged that to see slavery recognized upon soil once owned by Mexico would be so abhorrent to that government as it would be to the United States to see the Spanish Inquisition established upon it. Mr. Nicholas F. Trist, the American commissioner, gave a reply which a free Republic reads with increasing amazement. He declared that if the territory proposed to be ceded "were increased tenfold in value, and, in addition to that, covered a foot thick with pure gold, on the single condition that slavery should be forever excluded," he would not "entertain the offer for a moment, nor even think of sending it to his government. No American President would dare to submit such a treaty to the Senate."