Once upon a time, health care was simple: If you had a cut or hemorrhoids, you reached for a leech. There was no medical problem that couldn't be solved, in theory, by applying leeches to the body and letting the wild bloodletting begin. Now, it seems, some public-health experts have found a modern equivalent that will drain America of all its nasty public-health problems: tax increases. Thomas Frieden, the former New York City health commissioner who's now director of the Centers for Disease Control, has hailed taxes on sugary sodas as a painless way to reduce obesity -- despite much...