The states rights were the right of the states to have slaves.
Yep.
Guaranteed by the US Constitution in Article IV, section 2. When the Constitution was written, the vast majority of the states were slave states. Even those that weren't, ratified the provision of the Constitution which recognized the right of states to hold people in servitude by the laws of their state.
People want to ignore this, but for four score and seven years, the *UNION* was a legalized slavery Union. Had it maintained real constitutional law, it would have remained a slave Union till at least 1896.
The Union did maintain legalized slavery for six months longer than did the Confederacy. Funny that.