According to some Northern defenders in the Civil War Talk forum, the slave state of West Virginia entered the Union as a "free state." They argue this because they do not want to admit that Lincoln and his fellow Republicans displayed great hypocrisy in admitting a slave state to the Union six months after Lincoln issued the Emancipation Proclamation, since the proclamation called for the unconditional and immediate emancipation of all slaves in Confederate territory.
These Northern defenders claim that since West Virginia had to agree to a gradual emancipation plan, called the Willey Amendment, before being admitted, the state was a "free state" when it joined the Union in June 1863.
It is true that the Willey Amendment decreed that all children born to slave parents after July 4, 1863, would be born free, and that no slaves could enter the state for permanent residence. However, the amendment also kept all slaves who were then over the age of 21 enslaved until they died; it kept all slaves under the age of 10 enslaved until they turned 21; and it kept all slaves between the ages of 10 and 21 enslaved until they turned 25.
Why didn't Lincoln and the Republicans insist that the Emancipation Proclamation apply to West Virginia? The Radical Republicans called for the immediate emancipation of all slaves in Confederate territory, but they were willing to keep West Virginian slaves who were under 21 in bondage for four to 20 years, and to keep adult slaves in bondage for even longer in some cases.
By any logical, rational definition, West Virginia was a slave state when it joined the Union. When it entered the Union, over 18,000 slaves were being legally held within its borders, and all slaves under the age of 21 would remain enslaved for between four and 20 years, not to mention the fact that slaves over the age of 21 were not affected by the Willey Amendment and thus remained in bondage.
Here's the text of the Willey Amendment: