Two things about MJ smoking vs. tobacco: MJ smoke does not have all the dangerous chemicals that tobacco does - no nicotine. Also, if one smoked as much MJ as most smokers smoke tobacco, he would be incapacitated. I don't think that even Rastafarians can smoke the equivalent weight in MJ of 20-40 cigarettes a day.Certainly a reasonable question. Personally, I think that prohibition is on a downhill slide to legalization, right or wrong. I would bet though, you might find people who would agree that smoking should be banned, yet pot legalized. It is interesting that is seems to be two different directions at once. Moving to legalize marihuana which shares all the dangerous chemicals in the smoke plus more before we even consider its 'effect' yet we are going the other way on tobacco.
But I wouldn't be in favor of a prohibition of tobacco; alcohol prohibition and the War On Drugs have clearly shown that worse than being ineffective, such laws have worse side effects than the substances they are in opposition to in the form of violence, organized crime involvement, black markets, shadow economies, etc. But I don't look for the legalization of marijuana any time soon; it's too rewarding of a political football for our leaders to let go of. It is IMO hypocritical of our government to interdict against MJ growers and at the same time to subsidize the growing of tobacco, especially since tobacco use has killed far more people than all the illegal drugs combined.