4. To prevent states from prosecuting law abiding gun owners for abiding by this new federal law (and preventing challenges to the law based on entrapment grounds), any bill would need to preempt state level regulation of any item regulated under Title II of the National Firearms Act.

I think that such a bill could be proposed as an alternative to an ineffective and draconian ban being pushed by opponents of the 2nd amendment across the aisle. It would discourage the development of new workarounds to the National Firearms Act by allowing law abiding gun owners to own actual Title II items under strict regulation, but without the fear of state level persecution for their exercise of their 2nd amendment rights. Such a bill could be touted as a victory from both sides of the isle and would show the willingness of gun owners to consider public safety concerns.