Politicians across the Western world like to speak fondly of the “middle class” as if it is one large constituency with common interests and aspirations. But, as Karl Marx observed, the middle class has always been divided by sources of wealth and worldview. Today, it is split into two distinct, and often opposing, middle classes. First there is the yeomanry or the traditional middle class, which consists of small business owners, minor landowners, craftspeople, and artisans, or what we would define historically as the bourgeoisie, or the old French Third Estate, deeply embedded in the private economy. The other middle...