When in the progress of events the inhabitants of any Territory shall have reached the number required to form a State, they will then proceed in a regular manner and in the exercise of the rights of popular sovereignty to form a constitution preparatory to admission into the Union.  After this has been done, to employ the language of the Kansas and Nebraska act, they “shall be received into the Union with or without slavery, as their constitution may prescribe at the time of their admission.”  This sound principle has happily been recognized in some form or other by an almost unanimous vote of both Houses of the last Congress.

All lawful means at my command have been employed, and shall continue to be employed, to execute the laws against the African slave trade.  After a most careful and rigorous examination of our coasts and a thorough investigation of the subject, we have not been able to discover that any slaves have been imported into the United States except the cargo by the Wanderer, numbering between three and four hundred.  Those engaged in this unlawful enterprise have been rigorously prosecuted, but not with as much success as their crimes have deserved.  A number of them are still under prosecution.

Our history proves that the fathers of the Republic, in advance of all other nations, condemned the African slave trade.  It was, notwithstanding, deemed expedient by the framers of the Constitution to deprive Congress of the power to prohibit “the migration or importation of such persons as any of the States now existing shall think proper to admit” “prior to the year 1808.”  It will be seen that this restriction on the power of Congress was confined to such States only as might think proper to admit the importation of slaves.  It did not extend to other States or to the trade carried on abroad.  Accordingly, we find that so early as the 22d March, 1794, Congress passed an act imposing severe penalties and punishments upon citizens and residents of the United States who should engage in this trade between foreign nations.  The provisions of this act were extended and enforced by the act of 10th May, 1800.

Again, the States themselves had a clear right to waive the constitutional privilege intended for their benefit, and to prohibit by their own laws this trade at any time they thought proper previous to 1808.  Several of them exercised this right before that period, and among them some containing the greatest number of slaves.  This gave to Congress the immediate power to act in regard to all such States, because they themselves had removed the constitutional barrier.  Congress accordingly passed an act on 28th February, 1803, “to prevent the importation of certain persons into certain States where by the laws thereof their admission is prohibited.”  In this manner the importation of African slaves into the United States was to a great extent prohibited some years in advance of 1808.