From the CSA constitution:
" No bill of attainder, ex post facto law, or law denying or impairing the right of property in negro slaves shall be passed."
That is ironclad. Nothing of the sort exists in the US constitution.
The closest the US Constitution comes is in Article IV, Sec. 2, paragraph 3: "No Person held to Service or Labour in one State, under the Laws thereof, escaping into another, shall, in Consequence of any Law or Regulation therein, be discharged from such Service or Labour, But shall be delivered up on Claim of the Party to whom such Service or Labour may be due."
Do you think the Dred Scott decision was rightfully decided, considering this paragraph? I do; even though the majority opinion by CJ Taney seems to give the wrong reasons.