If New York Mayor Michael Bloomberg hadn't exposed disturbing violations of federal laws at gun shows in Arizona, who would have? Under federal law, unlicensed "occasional sellers" of the sort who peddle firearms at gun shows — or, for that matter, out of their homes or car trunks — aren't required to do an instant federal background check on purchasers. They are, however, supposed to turn away potential customers if they have reason to believe that person would be... (GunPolicy.org)