Gun-control laws, like all ill-advised measures, have unintended, often unfortunate, consequences. This is especially true in the post-Sept. 11, 2001, environment.Recently, Secretary of Homeland Security Tom Ridge upgraded the nation's alert status because of credible intelligence that several financial buildings in New York City; Newark, N.J.; and Washington, D.C. - including the building housing the New York Stock Exchange - are intended terrorist targets. Immediately, heavily armed, submachine-gun-toting government agents surrounded the buildings - five in all - and tightened security in the area. Police closed streets, rerouted traffic, established checkpoints and searched vehicles in the vicinity.What about other potential...