The system, however, had its defenders. Representatives from South Carolina argued that their entire economic life rested on slave labor and that the high death rate in the rice swamps made continuous importation necessary. Ellsworth of Connecticut took the ground that the convention should not meddle with slavery. "The morality or wisdom of slavery," he said, "are considerations belonging to the states. What enriches a part enriches the whole." To the future he turned an untroubled face: "As population increases, poor laborers will be so plenty as to render slaves useless. Slavery in time will not be a speck in our country." Virginia and North Carolina, already overstocked with slaves, favored prohibiting the traffic in them; but South Carolina was adamant. She must have fresh supplies of slaves or she would not federate. So it was agreed that, while Congress might regulate foreign trade by majority vote, the importation of slaves should not be forbidden before the lapse of twenty years, and that any import tax should not exceed $10 a head. At the same time, in connection with the regulation of foreign trade, it was stipulated that a two-thirds vote in the Senate should be necessary in the ratification of treaties. A further concession to the South was made in the provision for the return of runaway slaves--a provision also useful in the North, where indentured servants were about as troublesome as slaves in escaping from their masters. =The Form of the Government.=--As to the details of the frame of government and the grand principles involved, the opinion of the convention ebbed and flowed, decisions being taken in the heat of debate, only to be revoked and taken again. _The Executive._--There was general agreement that there should be an executive branch; for reliance upon Congress to enforce its own laws and treaties had been a broken reed. On the character and functions of the executive, however, there were many views. The New Jersey plan called for a council selected by the Congress; the Virginia plan provided that the executive branch should be chosen by the Congress but did not state whether it should be composed of one or several persons. On this matter the convention voted first one way and then another; finally it agreed on a single executive chosen indirectly by electors selected as the state legislatures might decide, serving for four years, subject to impeachment, and endowed with regal powers in the command of the army and the navy and in the enforcement of the laws.