I seem to recall a section in the US const or the Dec of In that placed a value on blacks to be far less than that of the white property owners of the time.
The Constitution has often been called a living tribute to the art of compromise. In the slavery question, this can be seen most clearly. The Convention had representatives from every corner of the United States, including, of course, the South, where slavery was most pronounced. Slavery, in fact, was the backbone of the primary industry of the South, and it was accepted as a given that agriculture in the South without slave labor was not possible. Though slaves were not cheap by any measure, they were cheaper than hiring someone to do the same work. The cultivation of rice, cotton, and tobacco required slaves to work the fields from dawn to dusk. If the nation did not guarantee the continuation of slavery to the South, it was questioned whether they would form their own nation.
Full article here
http://www.usconstitution.net/consttop_slav.html
Then there is the issue of the 13th and 14th and 15th amendments. I believe that this trumps the statement that they were state issues.
I do agree that more states should follow the lead of Virgina since the Federal Government is not willing to do what in my opinion would be the right thing.