But is diversity the key to prosperity and happiness? Or is diversity what naturally occurs when people from different backgrounds are drawn to a nation where prosperity can be earned and the pursuit of happiness is a founding principle?

In fact, Harvard political scientist Robert Putnam found that diversity hampers civic engagement: The greater the diversity, the less people engaged in charity and community projects. In the most diverse communities, people trust each other half as much as they do in the most homogenous settings.

Putnam, a pro-diversity fellow, didn’t particularly like his findings and has insisted that the data suggest challenges rather than excuses to avoid diversification. Hear, hear. But wouldn’t those challenges best be met by individuals discovering the rewards of diversity rather than by receiving the superior wisdom of bureaucrats through chirpy public service messages?