According to pewresearch.org, the percentage of those defined as the middle class in 1971 was 61% of all Americans, and a further 25% were considered to be lower class in 1971. As of 2016, the middle class has been reduced to 52% of all Americans, and the lower class has increased to 29%. This means that over the last two generations, that there are now more people that are actually part of the lower class then in 1971, and further that the vibrant middle class has been reduced to just barely half of all Americans, even though this country is a far richer country than it was in 1971. In fact, Elizabeth Warren stated in January of 2019, the "The top 0.1 percent, who'd pay my #UltraMillionaireTax, own about the same wealth as 90 percent of America."
One might think, with this type of income and wealth disparity, and living within a country in which the people as a whole, can avail themselves of the ballot box; in addition to the salient fact, that per its Constitution, this country permits a free press and therefore an open and vociferous debate about anything of merit, that America would never find itself suffering from such a tremendous disparity of inequality, but in fact, America does. More to the point, the situation is not self-correcting, but rather is getting worse.
The only conceivable explanation for the above, is that America is a class-based society in which rather than those that are losing ground and those that have never had any ground, actually standing strong together against the very small minority that hold all the cards, this has instead become a country in which the classes have turned against one other, so that as the middle class has proceeded to become more vulnerable and to lose ground, rather than that middle class constructively taking its frustrations and lack of fairness and addressing such against those in the wealthy minority that hold effectively the power, they have instead, far too often, bought into the construct that they are losing ground because of such dubious things such as illegal immigration, affirmative action, welfare programs, unions, and just about anything in which it is perceived that they are being robbed of their income in order to pay the idle, the stupid, and the unproductive.
The main reason why so many of the middle class spend an inordinate amount of time complaining and thereby taking out their aggression upon the lower class, is because, they recognize or believe strongly, that to attack the upper class is an exercise in futility that will only exacerbate their current situation and would most likely lead to a further erosion of their class, as well as the likelihood of a further loss of status and ultimately the shame of slipping into the disgrace of being lower class. Therefore, the middle class, often castigates the lower class, and believes that "law and order" and thereby the incarceration of so many for the basic crime of living within communities devoid of opportunity and any semblance of fairness, should be dealt with harshly, rather than ameliorated by strong government policies. So that, the rise of today's police state is because the upper class demands protection; while, the middle class demands that extralegal force be used to keep the lower class in their place; and the lower class suffers the indignity of being oppressively dealt with, and convicted literally, of the crime of being poor.