The states may well be the key, BUT they are firmly attached to the FedGov money spiggots.
We could use a Constitutional Convention to amend article V of the Constitution.
Article V describes how the Constitution is to be amended. The following is what needs to be amended from article V.
1. require a single issue convention only
2. the congress will have no part whatsoever in any constitutional convention
3. applications for a convention should be limited to one amendment
Then it will be safe to call a constitutional convention to amend the constitution.
Please read, excellent article on how to do this:
http://www.law.harvard.edu/students/orgs/jlpp/Vol30_No3_Rogersonline.pdf