Final answer:
Thomas Jefferson did not sign an act outlawing the importation of foreign slaves from Africa in 1808.
Step-by-step explanation:
False
In 1807, the U.S. Congress abolished the foreign slave trade, a ban that went into effect on January 1, 1808. After this date, importing captives from Africa became illegal in the United States. While smuggling continued to occur, the end of the international slave trade meant that enslaved domestic people were in very high demand.
Former tobacco farmers in Virginia and Maryland found themselves with 'surplus' enslaved people whom they were obligated to feed, clothe, and shelter. Virginia and Maryland therefore took the lead in the domestic slave trade, the trading of enslaved people within the borders of the United States.