WHO is happier about life — liberals or conservatives? The answer might seem straightforward. After all, there is an entire academic literature in the social sciences dedicated to showing conservatives as naturally authoritarian, dogmatic, intolerant of ambiguity, fearful of threat and loss, low in self-esteem and uncomfortable with complex modes of thinking. And it was the candidate Barack Obama in 2008 who infamously labeled blue-collar voters “bitter,” as they “cling to guns or religion.” Obviously, liberals must be happier, right? Wrong. Scholars on both the left and right have studied this question extensively, and have reached a consensus that it...