The state's working to 'exempt' their citizens are opening a potential Pandora's box. The IRS could decide that it will enforce federal law, regardless of state action - setting up a potential mess. Think of the current trend regarding marijuana. Federal agencies will enforce federal statutes - period.
This case involving the Pacific Legal Foundation is intriguing. There is one HUGE issue, however: This should not require court action. All that needs to happen is for the People's House to act and declare it void - no Senate or court action needed. The SCOTUS left the door open, in the same manner, regarding the 17th amendment - the House just never acted upon it. Boehner is the issue right now - we don't need the courts.