Supporters say vaping can help wean hard-core tobacco smokers off of cigarettes, much like methadone helps heroin addicts kick their drug habit. And the public health benefits are undeniable: Since vaping does not burn tobacco, it produces no tar residue, the toxin that causes emphysema and lung cancer.

But that hasn’t kept anti-vapers from pressing their case. They’ve pointed to the nicotine contained in some vaping liquids. Critics say that vaping is likely to turn a new generation of teenagers into nicotine fiends.

It’s hysteria for the most part, the kind of moral panic liberals love to stoke to justify a crackdown which invariably places government regulators - the ultimate kill-joys - in control of national policy.

But many and perhaps most vaping liquids contain no nicotine at all. Especially for first-time smokers, imbibing nicotine is not vaping’s primary appeal. Anti-vapers know this and have begun targeting the vaping liquid’s sweet-tasting flavor additives - 12,000 varieties and counting - that young adults especially find so appealing.

The main ingredients in vaping liquid, vegetable glycerin and propylene glycol, are not toxic when ingested. What happens when these same ingredients are burned at high temperatures? No one knows, but that hasn’t stopped a bevy of recent studies from concluding, with the flimsiest of evidence, that trace metals found in these liquids are likely to increase the risk for cancer.

But in a free society we do not start with the presumption of guilt and harm to stigmatize the pursuit of happiness.