<P> The United States Constitution of 1787 did not use the word "slavery" but included several provisions about unfree persons . The Three - Fifths Compromise (in Article I, Section 2) allocated Congressional representation based "on the whole Number of free Persons" and "three fifths of all other Persons". Under the Fugitive Slave Clause (Article IV, Section 2), "(n) o person held to service or labour in one state" would be freed by escaping to another . Article I, Section 9 allowed Congress to pass legislation to outlaw the "Importation of Persons", but not until 1808 . However, for purposes of the Fifth Amendment--which states that, "No person shall...be deprived of life, liberty, or property, without due process of law"--slaves were understood as property . Although abolitionists used the Fifth Amendment to argue against slavery, it became part of the legal basis for treating slaves as property with Dred Scott v. Sandford (1857). Socially, slavery was also supported in law and in practice by a pervasive culture of white supremacy . Nonetheless, between 1777 and 1804, every Northern state provided for the immediate or gradual abolition of slavery, except the border states of Maryland and Delaware . Maryland did not abolish slavery until 1864, and Delaware was one of the last states to hold onto slavery; it was still legal in Delaware when the thirteenth amendment was issued . No Southern state did so, and the slave population of the South continued to grow, peaking at almost four million people at the beginning of the American Civil War, when most slave states sought to break away from the United States . </P> <P> Lincoln understood that the Federal government's power to end slavery in peacetime was limited by the Constitution which before 1865, committed the issue to individual states . Against the background of the American Civil War, however, Lincoln issued the Proclamation under his authority as "Commander in Chief of the Army and Navy" under Article II, section 2 of the United States Constitution . As such, he claimed to have the martial power to free persons held as slaves in those states that were in rebellion "as a fit and necessary war measure for suppressing said rebellion". He did not have Commander - in - Chief authority over the four slave - holding states that were not in rebellion: Missouri, Kentucky, Maryland and Delaware, and so those states were not named in the Proclamation . The fifth border jurisdiction, West Virginia, where slavery remained legal but was in the process of being abolished, was, in January 1863, still part of the legally recognized, "reorganized" state of Virginia, based in Alexandria, which was in the Union (as opposed to the Confederate state of Virginia, based in Richmond). </P> <P> The Proclamation applied in the ten states that were still in rebellion in 1863, and thus did not cover the nearly 500,000 slaves in the slave - holding border states (Missouri, Kentucky, Maryland or Delaware) which were Union states . Those slaves were freed by later separate state and federal actions . </P> <P> The state of Tennessee had already mostly returned to Union control, under a recognized Union government, so it was not named and was exempted . Virginia was named, but exemptions were specified for the 48 counties then in the process of forming the new state of West Virginia, and seven additional counties and two cities in the Union - controlled Tidewater region . Also specifically exempted were New Orleans and 13 named parishes of Louisiana, which were mostly under federal control at the time of the Proclamation . These exemptions left unemancipated an additional 300,000 slaves . </P>

What states were affected by the emancipation proclamation