For a people who proudly enshrine individual freedoms in their founding document, Americans sure love telling each other what to do in their spare time. Consider a telling transatlantic pair of reactions to the proliferation of e-cigarettes, electronic devices that deliver all the nicotine of cigarettes but none of the carcinogenic smoke.

Noting pragmatically in a recent report that "quitting smoking is very difficult" and that "e-cigarettes are being used almost exclusively as safer alternatives to smoked tobacco," London's Royal College of Physicians recommended that the devices be promoted as such, urging regulators to tread carefully so as not to limit their potential to reduce harm.

Meanwhile, in Washington, the Food and Drug Administration's regulatory guns were blazing. The agency recently issued nearly 500 pages of rules extending its authority over e-cigarettes, imposing a series of requirements on makers and sellers, and dwelling on the threat of the devices, particularly to young people.

The FDA was in some respects catching up with the great American vaping crackdown. Philadelphia City Council added e-cigarettes to the city's indoor smoking ban (even though the devices are smokeless) back in 2014. California did the same last week while also prohibiting their sale to anyone under 21, with a college campus ban to follow. Fumed one state legislator: "The e-cigarette is nothing more than a new delivery system for toxic and addictive nicotine."

Actually, while nicotine is certainly addictive, it is not toxic to adults in the usual doses. The trouble with cigarette smoke is all the other stuff in it, which is what kills about half a million Americans a year.

Hence the public-health potential of electronic nicotine delivery. The Royal College of Physicians noted that the dangers of e-cigarettes are "unlikely to exceed 5 percent of the harm from smoking tobacco" and that there is little evidence that they are encouraging minors or anyone else to start smoking regular cigarettes. Nicotine gums and patches have long been approved as smoking cessation aids according to precisely the same principle - with the important difference that many smokers seem to (heaven forbid) enjoy using e-cigarettes.

Granted, vaping has exploded in popularity quickly and isn't risk-free. FDA oversight is welcome insofar as it ensures that the devices, and the liquids in them, are up to safety standards and not sold to children. But regulations that discourage or hamper their use by adult smokers will almost certainly cause more harm than good in the long run.

There could be other unintended consequences. If the FDA's rules are too onerous for the many small businesses in the vaping industry, for example, they could perversely ensure that the new market belongs to the big tobacco companies that can afford compliance. There is even evidence that e-cigarette age restrictions, however reasonable and intuitive, have encouraged more teens to use tobacco.

The rush to obliterate any distinction between cigarettes and e-cigarettes comes from the same impulse that drives some Americans' peculiar attachment to "abstinence only" sex education and punishment-oriented drug policies. Our moralistic aversion to harmful behaviors should yield to genuine compassion for those who are harmed.