THE TARIFF – A VOICE FROM SOUTH CAROLINA. – The Charleston Mercury, upon the question of a protective tariff, says: - “We trust that the members of Congress from the South will stand firm, and will rule out of all political or party association every man and any wing which may join the black republicans in this flagrant device of sectional plunder.” The same warning authority further remarks that, “already Southern Presidential aspirants, with their retainers and followers, have sought to sustain and keep in affiliation the traitor Douglas and his Northern clan, but that, protective tariff men included, “we trust the State Rights men in Congress will repudiate such allies, and purge the party of their corrupting presence and association.” This demand for mere “purging,” when the party has already been purged to the verge of the grave, is a very severe one. The party wants a tonic. Cuba will do; and even an incidental protective revenue tariff may strengthen the backbone of the party. In default of these specifics, it must be turned over to the undertaker. We agree with our Charleston contemporary however, upon the main point – that when the party has ceased to be true to its principles, whatever they may be, it were better that it ceased to exist.