OK, I get it.  Smoking in a car with a child is bad for the child's health, and s/he does not have a say.  But if government can ban that, then they also have to ban parents who buy only fast food for meals because it's quicker and easier than preparing healthy meals, ban parents from purchasing sodas for home use, candies and chips, etc.  In those cases, a child can choose, but if mommy and daddy are buying it, it sort of sends the message to the child that it's OK.  Will the parents hide from the child and consume those things so that the child is not influenced?   Unfortunately, poor parental habits often lead to poor childhood habits, but should the government step in whenever parents make poor choices?  If you do it for smoking, you have to do it for everything else!  (Poor diet, wreckless driving, swearing, drinking alcohol in excess....)