See Amendment the 13th.
The lack of slavery does not moot or vacate these rulings — on the Fugitive Slave Laws, including Dred Scott — as precedent law with regard to what may be done to citizens by Federal police dicta, and to whether the states can say “NOT CONSTITUTIONAL”. This is the way of judges who follow a morally neutral philosophy of stare decisis, who subsume and vacate long established common law principles, for the sake of stultifying chains of logic based off of vulgar distempered and faddish legislation.