This just and necessary rule of action, however, which limited their efforts to what the actual circumstances of the country would permit, made a clear distinction between a prohibition of the future importation of slaves, and the manumission of those already in the country. The former could be accomplished, if the consent of the people of the States could be obtained, without trenching on their sovereign control over the condition of all persons within their respective limits. It involved only the surrender of a right to add to the numbers of their slaves by continued importations. But the power to determine whether the slaves then within their limits should remain in that condition, could not be surrendered by the people of the States, without overturning every principle on which the system of the new government had been rested, and which had thus far been justly regarded as essential to its establishment and to its future successful operation. It is not, therefore, to be inferred, because a large majority of the Convention sought for a power to prohibit the increase of slaves by further importation, that they intended by means of it to extinguish the institution of slavery within the States. So far as they acted from a political motive, they designed to take away the power of a State to increase its congressional representation by bringing slaves from Africa; and so far as they acted from motives of general justice and humanity, they designed to terminate a traffic which never has been and never can be carried on without infinite cruelty and national dishonor. That the individuals of an inferior race already placed in the condition of servitude to a superior one may, by the force of necessity, be rightfully left in the care and dominion of those on whom they have been cast, is a proposition of morals entirely fit to be admitted by a Christian statesman. That new individuals may rightfully be placed in the same condition, not by the act of Providence through the natural increase of the species, but by the act of man in transferring them from distant lands, is quite another proposition. The distinction between the two, so far as a moral judgment is concerned with the acts of the framers of the Constitution upon the circumstances before them, defines the limits of duty which they intended to recognize.