On 19 June 1862, U.S. President Abraham Lincoln passed the Abolition of Slavery Act. On 1 January 1863, he issued the Declaration of Independence calling on the Union Army to free all slaves owned by landowners.
However, the effect of the Declaration did not have a proper impact until the end of the war, because its constitutionality was disputed by the very fact of an armed conflict between the North and the South. In December 1865, the 13th Amendment to the U.S. Constitution was passed abolishing slavery throughout the state. This event dealt the final blow to the slave trade in the country.
The Amendment was ratified by three-quarters of the U.S. states. They stated that neither slavery nor any other form of forced labour in the U.S. was no longer allowed. The victory of the North over the slave-owning South in the American Civil War (1861-1865) put an end to the importation of slaves into the country.
However, the slave trade on the American continent still continued until the end of the 19th century. It was finally banned in 1886 in Cuba and in 1888 in Brazil. The Convention on the complete prohibition of slavery and the slave trade was adopted by the League of Nations only in 1926.