While slavery and the conduct of slavery was generally governed by the states, numerous federal laws governed the slave trade.
1794 –US federal law prohibited the conduct of the slave trade from the United States to other countries. Ship and goods could be confiscated and fines were imposed
1800 –US federal law expanded to include the confiscation of goods, increased fines, provided for jail sentence for ships trafficking in slaves.
1803 – Federal law prohibited ships from transporting negroes, mulattos, or other persons of color into ports of states that prohibit slavery. Provided for confiscation of ships, cargo, and fines for each individual brought into port.
1807 – Federal law prohibited the importation of negroes, mulattos, or other persons of color into ports of all states, slave or free. Fines and jail terms significantly increased for those who did.
1850 – The Fugitive Slave Law allowed citizens of slave states to pursue their property (slaves) into free states and return home with their property. In 1854 fugitive slave Anthony Burns was caught in Boston and returned to his owner. Riots ensued and his freedom was bought eventually.
1863 – Emancipation Proclamation an executive order issued by President Lincoln January 1, 1863, during the American Civil War proclaiming the freedom of slaves in the ten states then in rebellion. About 3.1 million of the 4 million slaves in the U.S were eventually freed at that time. The Proclamation did not compensate the owners, did not itself outlaw slavery, and did not make the ex-slaves (called freedmen) citizens.
For more info: http://avalon.law.yale.edu/19th_century/fugitive.asp
Tomorrow, The Constitution, Supreme Court & Slavery Rita Bay