The slaveholding States have recognised this power in their laws.  The Virginia Legislature passed a law in 1786 to prevent the further importation of Slaves, of which the following is an extract:  “And be it further enacted that every slave imported into this commonwealth contrary to the true intent and meaning of this act, shall upon such importation become free.”  By a law of Virginia, passed Dec. 17, 1792, a slave brought into the state and kept there a year, was free.  The Maryland Court of Appeals at the December term 1813 (see case of Stewart vs. Oakes,) decided that a slave owned in Maryland, and sent by his master into Virginia to work at different periods, making one year in the whole, became free, being emancipated by the law of Virginia quoted above.  North Carolina and Georgia in their acts of cession, transferring to the United States the territory now constituting the States of Tennessee, Alabama and Mississippi, made it a condition of the grant, that the provisions of the ordinance of ’87, should be secured to the inhabitants with the exception of the sixth article which prohibits slavery; thus conceding, both the competency of law to abolish slavery, and the power of Congress to do it, within its jurisdiction.  Besides, these acts show the prevalent belief at that time, in the slaveholding States, that the general government had adopted a line of policy aiming at the exclusion of slavery from the entire territory of the United States, not included within the original States, and that this policy would be pursued unless prevented by specific and formal stipulation.

Slaveholding states have asserted this power in their judicial decisions. In numerous cases their highest courts have decided that if the legal owner of slaves takes them into those States where slavery has been abolished either by law or by the constitution, such removal emancipates them, such law or constitution abolishing their slavery.  This principle is asserted in the decision of the Supreme Court of Louisiana, in the case of Lunsford vs. Coquillon, 14 Martin’s La.  Reps. 401.  Also by the Supreme Court of Virginia, in the case of Hunter vs. Fulcher, 1 Leigh’s Reps. 172.  The same doctrine was laid down by Judge Washington, of the United States Supreme Court, in the case of Butler vs. Hopper, Washington’s Circuit Court Reps. 508.  This principle was also decided by the Court of Appeals in Kentucky; case of Rankin vs. Lydia, 2 Marshall’s Reps. 407; see also, Wilson vs. Isbell, 5 Call’s Reps. 425, Spotts vs. Gillespie, 6 Randolph’s Reps. 566.  The State vs. Lasselle, 1 Blackford’s Reps. 60, Marie Louise vs. Mariot, 8 La.  Reps. 475.  In this case, which was tried in 1836, the slave had been taken by her master to France and brought back; Judge Mathews, of the Supreme Court of Louisiana, decided that “residence for one moment” under the laws of France emancipated her.