American Civil War - US Constitution and Bill of Rights on Slavery
The Constitution on Slavery: By the time the United States Constitution was drafted in 1878, slavery had existed in the American colonies for 168 years. Whether slavery was permitted to be continued under the Constitution was argued. Southern colonies simply would not join the Union if slavery was made illegal. So, although the word slave or slavery is not found in the Constitution, it was clearly allowed to have slaves. The Constitution states in Article 1, Section 2, that "all other persons" meaning slaves, are each counted as three-fifths of a white person for the purpose of assigning a number of representatives to the Congress and Senate based on state population.
The Bill of Rights on Slavery: The Fifth Amendment of the Bill of Rights states that no person could "be deprived of life, liberty, or property, without due process of law." Slaves were property, by law. And thus slavery continued to be legal in the United States of America.