Dear Editor: Add one more dumb idea to those being advanced in Washington: allowing loaded guns in our national parks. Under longstanding Department of the Interior regulations, firearms are permitted in national parks only if unloaded and stored. The National Rifle Association has pressured Congress and the current administration to change this rule and to permit loaded and concealed guns if allowed by state law. The administration has yielded. I call the idea dumb because the absence of firearms is perhaps the biggest reason why the national parks are now virtually free of violent crime. Sanctioning people to carry and potentially use firearms invites crime into one of our last peaceful family sanctuaries. Even if not used for criminal activities, loaded firearms are highly dangerous among persons in a crowded outdoor environment who are unreasonably anxious over wildlife and the conduct of strangers. Please join the many groups and individuals who oppose allowing loaded firearms in our national parks. Make your opposition known to the administration (Department of the Interior) and to the members of Congress.