The basic case against New York Mayor Michael Bloomberg’s latest crusade, to outlaw the sale of extra- large sugared soft drinks, is Libertarianism 101: In a free country, people should have the right to do what they want, even if it’s bad for them. The major exceptions and complications to this basic principle don’t seem to apply. Unlike secondhand smoke, my consumption of a Pepsi does no direct harm to anyone else. Unlike marijuana, sugary drinks have a perfectly adequate and legal substitute: sugar-free drinks. (Even if you can tell the difference between Coke and Diet Coke, you can’t claim...