Westen’s thesis is simple. “A dispassionate mind that makes decisions by weighing the evidence and reasoning to the most valid conclusions bears no relation to how the mind and brain actually work.” That’s true when it comes to choosing a significant other, buying a car, and choosing a president. Madison Avenue has known this for decades. Democrats haven’t. Instead, their strategists start from an 18th-century vision of the mind as dispassionate, making decisions by rationally weighing evidence and balancing pros and cons. That assumption is a recipe for high-minded campaigning—and, often, electoral failure.