I support strong gun rights, but I don't think
this suggestion from Akhil Amar is the way to do it. "That's how a lot of states have always done it" could be used to justify . . . well, almost anything, including some really repulsive things. I think this particular social contract needs to be a little more explicit than "Whatever the neighbors are doing is all right."
This article available online at:
http://www.theatlantic.com/business/archive/2008/03/gun-rights-not-that-way/3026/