It has not been done at all. It has been declared to have been done, but there is no actual philosophical or legal underpinning to their claims.
They do what the media does. Allege something, and then keep repeating that they proved it.
I've asked a clearly provable question. How does an asserted "Contraband of War" claim overcome an actual constitutional clause?
Denial is a river in Egypt, not a valid defense.
The Confiscation Acts were laws passed by the United States Congress during the Civil War with the intention of freeing the slaves still held by the Confederate forces in the South.
The Confiscation Act of 1861 authorized the confiscation of any Confederate property by Union forces (”property” included slaves). This meant that all slaves that fought or worked for the Confederate military were confiscated whenever court proceedings “condemned” them as property used to support the rebellion. The bill passed in the United States House of Representatives 60-48 and in the Senate 24-11. The act was signed into law by President Lincoln on August 6, 1861.
I could be wrong, but I believe the constitution allows congress to pass laws.