into law by President Thomas Jefferson (who had called for its enactment in his 1806 State of the Union address), went into effect on January 1, 1808, the earliest date on which the importation of slaves could be prohibited under the Constitution. The delegates approved the Fugitive Slave Clause of the Constitution (Article IV, section 2, clause 3), which prohibited states from freeing slaves who fled to them from another state and required that they be returned to their owners. The Fugitive Slave Act of 1793 and the Fugitive Slave Act of 1850 gave effect to the Fugitive Slave Clause. Three-fifths Compromise In a section negotiated by James Madison of Virginia, Section2 of ArticleI designated "other persons" (slaves) to be added to the total of the state's free population, at the rate of three-fifths of their total number, to establish the state's official population for the purposes of apportionment of congressional representation and federal taxation. The "Three-Fifths Compromise" was reached after a debate in which delegates from Southern (slaveholding) states argued that slaves should be counted in the census just as all other persons were while delegates from Northern (free) states countered that slaves should not be counted at all. The compromise strengthened the political power of Southern states, as three-fifths of the (non-voting) slave population was counted for congressional apportionment and in the Electoral College, although it did not strengthen Southern states as much as it would have had the Constitution provided for counting all persons, whether slave or free, equally. In addition, many parts of the country were tied to the Southern economy. As the historian James Oliver Horton noted, prominent slaveholder politicians and the commodity crops of the South had a strong influence on United States politics and economy. Horton said, in the 72 years between the election of George Washington and the election of Abraham Lincoln, 50 of those years [had] a slaveholder as president of the United States, and, for that whole period of time, there was never a person elected to a second term who was not a slaveholder. The power of Southern states in Congress lasted until the Civil War, affecting national policies, legislation, and appointments. One result was that justices appointed to the Supreme Court were also primarily slave owners. The planter elite dominated the Southern congressional delegations and the United States presidency for nearly fifty years. 1790 to 1860 Slave trade