The original American reference to a "middle class" probably comes from Britain. It referred, as on the continent, to the propertied but untitled yeomanry of the countryside, the rising burghers in the cities, and the mercantile classes as a whole. It was an accurate naming. What was to become the bourgeoisie really did originally stand between the aristocracy and the property-less classes.
The next stage in this evolution was the rise of the absolute monarchies with the former middle class becoming a major, and sometimes equal, pillar of the state, alongside the aristocracy (the "Third Estate" in France, as an example). In Britain, this evolution was stillborn in many ways because the British bourgeoisie came to power much earlier than in many other countries (in the Civil War of 1648). The English bourgeoisie followed regicide with a “restoration” of a slavish monarchy, and then merged the old aristocracy with itself. Large estates became alienable, titles could be bought and sold, and the monarchical institutions became largely ceremonial. In turn, the middle class "gentlemen" of the 18th century really were an income tier - possessing enough property to avoid the coarser trades but lacking the wherewithal to buy title and transcendence. The Americas were colonized by such... or at least the local power descended from such.
At this point, the meaning of middle-class diverges. On the Continent, the middle-class came to be a description of the mass of small property holders, owning their own means of production but typically employing only their own labor or perhaps a handful of others and even that, often seasonally. This is the infamous "petite-bourgeoisie" and it owed its infamy to its instability. Aspiring to raise itself within the ranks of the property owners on the one hand, it was continuously expropriated and diminished in numbers on the other. The story of the next 100 years of European history is precisely that story.
In Britain, a similar process transpired, but with two counteracting influences. Just as in Europe, the lands were "cleared" and the small holders were expropriated, but at the same time the British mercantile monopolies bore fruit. A worldwide colonial empire was transformed into the engine of capital accumulation and its essential product was the industrial revolution. In both cases, it was not just a vast army of proletarians who were created but also a sea of unusually skilled “labor aristocrats”, specialists, managers, colonial officials, minor civil servants, and professionals of every type and description. This was more a new social stratum than a class, but it echoed some of the perspectives of that which came before it, and it was dependent on and wedded to the social system of Empire. It was not so much that the proceeds of Indian labor went to London bank clerks, as it was that Indian banks were located in London… certainly their management and their hierarchy of favored positions was located in London. This is the genesis of the transformation of the British middle-class, from a continental to an Imperial definition.
That British middle-class, the source of endless political stability and social philistinism, lasted as long as the Empire and industrial ascendancy did. The bankruptcy of that Empire after WW2 and its rapid dismantling also ended the rein of middle-class politics. Politics, in turn, was just a reflection of the decomposition of the “class”, itself. While middle-class nostalgia was producing Thatcher Tories, the British standard of living was falling to the same level as that of Italy or Portugal. Today, few such illusions remain, although a “New” Britain has risen in the nexus of EU and American economics.
With this allegory in mind, it is possible to look at America. While, the origin of the term may be British, for most of its history, the American middle-class went by a Continental definition. America was a “middle-class” country from its inception… built on “free” land (in the dual sense… i.e. also “freed” from its former inhabitants). As late as the decades after the Civil War, 70% of the population owned their own means of production, even if it was modest in most cases. The subsequent transformation of that status was partly the operation of the very same forces as we have already described and partly the result of the flood of European immigrants, recently freed from their property. Daveparts has referred to the backwardness of rural America in the 1930s. On this, he is quite right. In approximately 60 years, the population of freeholders fell from 70% to less than 10%. It is less than 5% today, once the various tax schemes and contractor rackets are abstracted away. The story of America before the War is the story of The Grapes of Wrath and in no way could the U.S. be accurately described as a “middle-class country”.
So what has changed, since? Was it FDR, the New Deal, Democrats… a new “Enlightenment” perhaps? In fact, it was a positive outcome to the Second World War. What Britain lost, the U.S. inherited. And among that inheritance was a new definition for “middle-class”, adopted from the English. Social mobility, the movement up the division of labor, a certain level of prosperity, advancement through education… and all of it made possible from industrial ascendancy and the fact that Indian banks were now located in New York. The end of that era comes with globalization. It makes little difference whether the new era produces a new capitalist competition or whether the very success of American Empire relocates Indian banks to India. The inevitable result will be the decomposition of the American middle-class and there is not a single political perspective which promises otherwise. It is the division of misery in the decline that is in question.
I don’t agree with Chlamor that there is a physical shortage of physical material which prevents a generalization of middle-class prosperity worldwide. But, once past that disagreement, the argument is moot because he might as well be right. Capitalism does not elevate… it expropriates and impoverishes. Its urban slums and shanty towns are a step down from the rural, quasi-capitalist material it begins with. Worldwide, it expropriates wealth from the many instead of creating “prosperity”. It is only in microcosm that it appears otherwise.
On PopI, there are some charts on postwar income in the U.S. which I can’t currently find but which I will look for again. They divide U.S. income into a hierarchy of 10 tiers, each representing 10% of the population, and then project that income forward from WW2. For something like 20 years, the top seven or eight of the ten reach upwards… until they stall in the 1960s and 70s. After that, one after another, the next highest tier stagnates… sometimes even falls… until only a couple of tiers continue to advance. Meanwhile, the “lifestyle” is temporarily maintained through two incomes, and then through huge debt and home equity loans, followed by the first general drop in home ownership and the first general reversal of “liquidity” in a generation. The story is straightforward.
All attempts to paint the existence of the middle-class as an aspect of “politics” or policy, positively or negatively, are simply wrong. The "middle-class" is a historically created, changing, and ultimately decomposing social structure which is no more a permanent part of America than Conestoga Wagons or the railroads.