Mr. Martin thus gives the well-known history of the compromise involved in this clause:--
"This clause was the subject of a great diversity of sentiment in the Convention. As the system was reported by the committee of detail, the provision was general, that such importation should not be prohibited, without confining it to any particular period. This was rejected by eight States; Georgia, South Carolina, and, I think, North Carolina, voting for it.
"We were then told by the delegates of the two first of those States, that their States would never agree to a system which put it in the power of the general government to prevent the importation of slaves; and that they, as delegates from those States, must withhold their assent from such a system.
"A committee of one member from each State was chosen by ballot to take this part of the system under their consideration, and to endeavor to agree upon some report which should reconcile those States. To this committee also was referred the following proposition, which had been reported by the committee of detail, to wit: 'No Navigation Act shall be passed without the assent of two-thirds of the members present in each house;'--a proposition which the staple and commercial States were solicitous to retain, lest their commerce should be placed too much under the power of the Eastern States; but which these last States were as anxious to reject. This committee, of which also I had the honor to be a member, met, and took under their consideration the subjects committed to them. _I found the Eastern States, notwithstanding their aversion to slavery, were very willing to indulge the Southern States, at least with a temporary liberty to prosecute the slave-trade, provided the Southern States would in their turn gratify them, by laying no restriction on Navigation Acts_; and, after a very little time, the committee, by a great majority, agreed on a report, by which the general government was to be prohibited from preventing the importation of slaves for a limited time, and the restricted clause relative to Navigation Acts was to be omitted.
"This report was adopted by a majority of the Convention, but not without considerable opposition."