Presume every single one of my semi-urban middle-class, middle-aged female neighbors does yoga. Enter Marianne Williamson.In addition to being a Democratic presidential contender, Williamson is some sort of a failed actress who was big in Los Angeles in the 1980s—not as an actress, but as a New Age guru. She is an author of several best-sellers on the topic of “metaphysics,” and she’s been on “Oprah†countless times. She officiated an Elizabeth Taylor wedding, remains popular with Hollywood celebrities, and is endorsed by former presidential contender Dennis Kucinich.A charismatic cult leader, Williamson advises her followers to forego science-based Western...