Laws against drinking and driving make sense; they prevent people from doing dangerous things. It's not really different from laws against setting off explosives on your lawn or throwing rocks onto an underpass. You need to regulate activity that will likely lead to harm, not simply punish those people who actually cause harm, or as GUEST has said it will be bloody dangerous out there. While I have no problem with someone smoking a joint or a cigarette in private, provided they don't go driving while stoned, public smoking of ANYTHING should be illegal. No factory would be allowed to dump that concentration of carcinogens and toxins into the air or a water supply, so why should private citizens get away with it?