New York City Mayor Michael Bloomberg's proposed ban on big sodas in the Big Apple is generating accusations that he is a Nanny Statist. But that's not quite accurate. A nanny forces others to do things for their own good. Bloomberg is a moral narcissist forcing New Yorkers to do things that make him feel good.

Under his soda ban, street vendors and restaurants would be barred from selling pop in anything over 16-ounce containers on the theory that limiting access to sugary drinks will help combat the city's obesity and diabetes "epidemics." No one—not even Bloomberg himself—believes that the ban will actually work, not least because unlimited free refills will remain legal, as will oversized helpings of apple juice and other "natural" beverages with arguably even more sugar. But workability isn't the point right now. It's to get the public used to the idea of the government slurping around in your Slurpee, and then to ratchet up. It's the slippery slope consciously deployed as a policy strategy.

Nor is this Bloomberg's first foray into minding your own business. He has also cracked down on smoking, salt and trans fats. He has mandated that fast-food joints post calorie counts. He also tried (unsuccessfully) to bar food stamp recipients from buying sodas—one-upping fellow Republicans who want to urine-test welfare recipients to make sure they don't use their government aid for drugs.

Alleged public health threats are not Bloomberg's only obsession. Although himself an admitted former toker, he has unleashed the nation's most insidious anti-pot policy in defiance of state law. New York decriminalized the possession of less than 25 grams of marijuana so long as it is not in public view. But the NYPD started entrapping suspects through a "stop-and-frisk" strategy that forces them to empty their pockets when stopped—and arrests them if any dope comes into public view.

This has made New York the marijuana arrest capital of the world. Over 400,000 low-level marijuana arrests have been made during Bloomberg's tenure, more than in the three previous administrations combined. The vast majority of them occur in poor, minority neighborhoods, ruining the lives of young Latino and black men for acts that their richer, whiter bros in tonier suburbs get away with routinely. Local outrage is finally prompting Gov. Andrew Cuomo to make low-level pot possession a misdemeanor not punishable by arrest. The soda ban too, it should be noted, will have a disproportionate impact on the budget of low-income families, who often buy a large pop and share.

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How does Bloomberg get away with such ruinous interference? Essentially, by affixing the adjective "public" before his pet peeves, turning them into respectable social causes such as "public health" and "public security." The truth is that people who enjoy Twinkies and cola turn off Bloomberg, a rich man with an ultra-yuppie sensibility. But he can't simply outlaw their preferences and mandate his. In the "free" world, rulers have to offer rationales beyond their personal whims. And the one Bloomberg and his fellow social engineers increasingly deploy doesn't involve compelling individuals to undertake virtuous actions to advance some broader public good (something that can be constitutionally nettlesome, as Obamacare's individual mandate demonstrated). Rather, it involves barring individuals from doing things to prevent some public harm—a negative externality, to use economics parlance.

This occurs when one person's actions have harmful side effects for another. A factory dumping effluents into a river and hurting downstream farmers, for example. Its prerequisite is some commonly held resource that no one—not even the most ardent libertarian—could argue individuals have the right to ruin for personal gain.

Hence social meddlers have taken to finding such externalities everywhere—and then asserting jurisdiction over them. Liberal blogger Felix Salmon has declared private schools a negative externality (presumably worthy of outlawing) because they hurt state-run schools, a public resource. Global-warming warriors have ordained the Earth's climate a global common that everyone needs to go on a strict energy diet to protect. Likewise, as far as Bloomberg is concerned, government spending has made health care a common concern—one he has to address by vetting individuals' diets.

Every Bloomberg edict has been accompanied by a strange kind of doublespeak: He at once denies he's restricting anyone's rights even as he identifies the public interest requiring those rights to be restricted. He justified his crackdown on non-violent pot users by citing potential savings to the city's security budget in case they turn violent. His public health commissioner Tom Farley is flirting with alcohol restrictions on everyone because some people might drink excessively and require costly emergency care. When banning trans fats, Bloomberg insisted that he was not "taking away anybody's ability to eat what they want"—he was merely "trying to make food safer" to minimize cardiac-related public health costs. Likewise, he defended his clampdown on sugary drinks by protesting, "We're not taking away anyone's rights to do things. We're simply forcing you to understand [that your choices have public costs]."

But public costs are simply a ruse for control freaks like Bloomberg to foist their personal choices on everybody else. To stop them will ultimately require restricting government to its essential functions. Until then, New Yorkers need to tell Bloomberg that they will gladly spend a little extra on people's "unhealthy" choices as a price for their liberties. Protecting their rights is more important than protecting their pocketbooks.

Reason Foundation Senior Analyst Shikha Dalmia is a columnist at The Daily, where this column originally appeared.

