During late years the Slave Power has introduced a new test for office, which would have excluded Washington, Jefferson, and Franklin. It applies an arrogant and unrelenting ostracism to all who express themselves against Slavery. And now, in the madness of tyranny, it proposes to extend this curse over new soil not yet darkened by its presence. It seeks to make the flag of our country the carrier of Slavery into distant lands,--to scale the mountain fastnesses of Oregon, and descend with its prey upon the shores of the Pacific,--to cross the Rio Grande, and there, in broad territories, recently wrested from Mexico by robber hands, to plant a shameful institution which that republic has expressly abolished. In the prosecution of its purposes, the Slave Power has obtained the control of both the great political parties. Their recent nominations were made to serve its interests, to secure its supremacy, and especially to promote the extension of Slavery. Whigs and Democrats,--I use the old names still,--professing to represent conflicting sentiments, concur in being representatives of the Slave Power. General Cass, after openly registering his adhesion to it, was recognized as the candidate of the Democrats. General Taylor, who owns slaves on a large scale, though observing a studious silence on Slavery, as on all other things, is not only a representative of the Slave Power, but an important constituent part of the Power itself. I will not dwell upon the manner in which General Taylor was forced upon the late Whig party. This has been amply done by others. But you will pardon me, if I allude to the aid his nomination derived from a quarter of the country where it should have encountered inexorable opposition,--I refer to New England, and especially to Massachusetts. I speak only what is now too notorious, when I say that it was the secret influence which went forth from among ourselves that contributed powerfully to this consummation. Yes! it was brought about by an unhallowed union--conspiracy let it be called--between two remote sections: between the politicians of the Southwest and the politicians of the Northeast,--between the cotton-planters and flesh-mongers of Louisiana and Mississippi and the cotton-spinners and traffickers of New England,--between the lords of the lash and the lords of the loom.