It might undoubtedly have been considered that, as the want of a power in the Confederation to make uniform commercial regulations affecting the foreign and domestic relations of the States was one of the principal causes of the assembling of this Convention, such a power was implied in the terms of the resolution, which had declared the general principles on which the authority of the national legislature ought to be regulated. Still, it remained to be determined what kind of regulation of commerce was required by "the general interests of the Union," or how far the States were incompetent, by their separate legislation, to deal with the interests of commerce so as to promote "the harmony of the United States." In the same way, a power to obtain revenues might be implied on the same general principles. But whether the commercial power foreshadowed in these broad declarations was to be limited or unlimited; whether there were any special objects or interests to which it was not to extend; and whether the revenues of the government were to be derived from imposts laid at pleasure upon imports or exports, or both; whether they might be derived from excises on the manufactures or produce of the country; whether its power of direct taxation was to be exercised under further limitations than those already agreed upon for the apportionment of direct taxes among the States;--all these details were as yet entirely unsettled. Two subjects, one of which might fall within a general commercial power, and the other within a general power to raise revenues, had already been incidentally alluded to, and both were likely to create great embarrassment. General Pinckney had twice given notice that South Carolina could not accede to the new Union proposed, if it possessed a power to tax exports.[211] It had also become apparent, in the discussions and arrangements respecting the apportionment of representatives, that the possible encouragement of the slave-trade, which might follow an admission of the blacks into the rule of representation, was one great obstacle, in the view of the Northern States, to such an admission; and at the same time, that it was very doubtful whether all the Southern States would surrender to the general government the power to prohibit that trade.[212] The compromise which had already taken place on the subject of representation had settled the principles on which that difficult matter was to be arranged. But the power to increase the slave populations by continued importation had not been agreed to be surrendered; and unless some satisfactory and reasonable adjustment could be made on this subject, there could be no probability that the Constitution would be finally ratified by the people of the Northern States.[213] It is necessary, therefore, to look carefully at these two subjects, namely, the taxation of exports and the prohibition of the slave-trade.