A Dutch ship brought the first African slaves to the shores of Virginia in the late 17th century. Though Congress enacted several restrictions and partial bans to curb its practice, the “peculiar institution” of slavery remained legal in full or in part in the United States for more than 200 years. The document that finally banned slavery throughout the country was the 13th Amendment to the Constitution which was passed in 1865.

Early Restrictions on the Slave Trade

The Act Prohibiting the Importation of Slaves, passed by Congress and signed into law by President Thomas Jefferson, forbade the importation of foreign born slaves "into any port or place within the jurisdiction of the United States.” The law, which went into effect on January 1, 1808, forbade Americans from participating in the international slave trade. If they were found guilty of doing so, they faced up to $10,000 in fines and up to 10 years in jail. Also, American citizens found guilty of buying foreign-born slaves were subject to an $8000 fine for each slave purchased. The domestic slave trade, however, was unaffected by the Act of 1807.

Early Partial Bans on Slavery

In the years following the American Revolutionary War, the northern states each passed laws restricting slavery within their borders. For example, Vermont drafted a prohibition on slavery into its state constitution in 1777, while Pennsylvania enacted a gradual emancipation law in 1780. The Second Continental Congress prohibited the practice of slavery in the territories northwest of the Ohio River with the passage of the Northwest Ordinance of 1787. The Missouri Compromise, passed by Congress in 1820, permitted slavery in the new state of Missouri but forbid the practice in the Louisiana Territory. Each of these laws, however, only applied to particular regions within the United States. A full ban on slavery that applied to the whole country would require an amendment to the U.S. Constitution.

Emancipation Proclamation

On January 1, 1863, in the midst of the American Civil War, President Abraham Lincoln issued the Emancipation Proclamation which granted freedom to all slaves held in states still in rebellion to against the Union. This Proclamation did not apply, however, to slaves held in border states that were loyal to the Union or Confederate territories that had fallen under the control of the Union. Additionally, the permanent freedom promised by the Emancipation Proclamation depended upon a Union victory in the war.

Amending the Constitution

Congress first attempted to ban slavery with an amendment to the Constitution in April of 1864. While the amendment passed in the Senate, the measure languished in the House of Representatives with several House Democrats withholding approval in favor of states' rights. However, after adding the abolition of slavery to the Republican Party platform, the Republicans gained a significant majority in both houses of Congress in the elections held later that same year.

The Thirteenth Amendment

On January 31, 1865, the House of Representatives passed the 13th Amendment with a vote of 119 to 56. The next day, President Lincoln approved the measure and sent it to the states for ratification. By Dec. 6, 1865, the necessary three-fourths of the states in the Union had ratified the amendment and slavery was officially banned in the United States. The 13th Amendment states that "neither slavery nor involuntary servitude, except as a punishment for crime whereof the party shall have been duly convicted, shall exist within the United States, or any place subject to their jurisdiction."