The second amendment reads:
A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed.
As evidenced by the events of Aurora and now Newtown, a person in possession of multiple weapons may constitute a militia.
I propose that owning more than two handguns and/or two rifles shall constitute a militia and be subject to regulation, including, but not limited to: licensing, including annual mental examinations, mandatory registry of weapons, mandatory recordation of sales, substantial fines for losing weapons and mandatory insurance, including strict co-liability for any criminal use of weapons.