As soon as the Constitution was ratified, the states were no longer sovereign. It took a while for it to become obvious, and for all the various supreme court cases interpreting the constitution to pile up, but it was a fait accompli. The Constitution killed state sovereignty.
Still can't agree. State sovereignty is plainly stated in the Bill of Rights. I agree that the Supreme Court didn't help matters, by ignoring the Ninth and Tenth Amendments, but the outcome was far from inevitable. It took an illegal war to accomplish.