As a traditional, individual rights advocating "liberal" I have often, on these discussion boards, advocated a way to expand background checks and include gun owners in the effort to prevent prohibited persons from obtaining such weapons.  Simply open the prohibited persons database to direct public access.  It meets every goal: protects innocent persons from potentially meeting a documented criminal, protects innocent citizens' privacy, and denies documented criminals the opportunity to obtain weapons.  The current methods of obtaining weapons by criminals would probably continue, such as smash and grab gun store attacks, but at least we could focus the resources and efforts on upgrading the prohibited persons lists and securing weapons caches.