You may be thinking of the 10th amendment. Correct me if I'm wrong.
http://archives.gov/exhibits/charters/b ... cript.html
That being said, I think Ron Paul's whole arguement is not so much conflation of state's rights with people's rights, but with limiting the federal government's authority and allowing the citizens of states some degree of self determination. After all, in a sense the U.S. is not "one state", but fifty, The U.S. is merely the union.
Just explaining my take on it, not neccessarily my personal opinion, though I am sympathetic to Paul's aims (wouldn't be here if I wasn't.).