Planters feared that group meetings would facilitate communication among slaves that could lead to rebellion. Slaves held private, secret "brush meetings" in the woods. In Ohio, an emancipated slave was prohibited from returning to the state in which he or she had been enslaved. Other Northern states discouraged the settling of free blacks within their boundaries. Fearing the influence of free blacks, Virginia and other Southern states passed laws to require blacks who had been freed to leave the state within a year (or sometimes less time) unless granted a stay by an act of the legislature. High demand and smuggling The United States Constitution, adopted in 1787, prevented Congress from completely banning the importation of slaves until 1808, although Congress regulated against the trade in the Slave Trade Act of 1794, and in subsequent Acts in 1800 and 1803. During and after the Revolution, the states individually passed laws against importing slaves. By contrast, the states of Georgia and South Carolina reopened their trade due to demand by their upland planters, who were developing new cotton plantations: Georgia from 1800 until December 31, 1807, and South Carolina from 1804. In that period, Charleston traders imported about 75,000 slaves, more than were brought to South Carolina in the 75 years before the Revolution. Approximately 30,000 were imported to Georgia. By January 1, 1808, when Congress banned further imports, South Carolina was the only state that still allowed importation of enslaved people. The domestic trade became extremely profitable as demand rose with the expansion of cultivation in the Deep South for cotton and sugar cane crops. Slavery in the United States became, more or less, self-sustaining by natural increase among the current slaves and their descendants. Maryland and Virginia viewed themselves as slave producers, seeing "producing slaves" as resembling animal husbandry. Workers, including many children, were relocated by force from the upper to the lower South. Despite the ban, slave imports continued through smugglers bringing in slaves past the U.S. Navy's African Slave Trade Patrol to South Carolina, and overland from Texas and Florida, both under Spanish control. Congress increased the punishment associated with importing slaves, classifying it in 1820 as an act of piracy, with smugglers subject to harsh penalties, including death if caught. After that, "it is unlikely that more than 10,000 [slaves] were successfully landed in the United States." But, some smuggling of slaves into the United States