Again, don't create laws for all parents because there are excemptions. For the law we are all the same, so if you create laws to monitor parental decisions everyone is subject to them. Her individual rights should be protected, but the parent has rights also. It's a thin line you are walking on here.
I'm not saying parents should be monitored to ensure that they aren't smoking in front of their children, any more than the state currently monitors its citizens to make sure that their citizens aren't currently murdering someone.
I'm simply stating that the state could make it illegal to smoke in the car with your children also in the car. If you drove past a police officer who saw you doing it, he could pull them over. He can already pull you over if he sees you smoking a joint. Why not a cigarette?
I dont agree that the sate should take care of them, their community (family, friends) should first. State should come stone dead last.
That already happens in cases of child abuse.
If you want to talk about risks, consider this; more people die on the road then from smoking.
That's because there are vastly more drivers than smokers. Smokers are more likely to die from lung cancer than from car accidents. Smokers on average die 10 years younger.
Where do you draw the line? And what makes you think that line is just?
That is for society to decide through reasoned debate. Clearly both extremes are unacceptable. We cannot have it legal for you to do whatever you like to your children (e.g. child slavery, child abuse, throwing your child down a well etc) and we cannot have it illegal for you to expose your children to risk - particularly since many risks that children are exposed to expand their life view and are actively good for them. Thats why we allow school trips.
But smoking massively harms children and provides no benefit to them. So I propose that we make it illegal to smoke in cars when your children are in the car. What you do in your house is up to you (because the intrusiveness of monitoring it outweighs the benefit) and what you do in your car when your children aren't in it is up to you.
You can have laws making it illegal to inflict physical harm upon other persons, you can't have laws forcing people to become better parents.
I'm not suggesting a law to make you a good parent. I'm suggesting one to stop you maliciously or negligently filling your children's lungs with smoke and reducing their life expectancy by 10 years when they are in your car in public.