Blaming Everything on Overpopulation
According to Peter Turchin, today's politics is due to overpopulation:
In other words, the population of workers—according to this theory—is growing faster than the population of employers. On the other hand,
Workers or employees make up the bulk of any society, with a minority of employers constituting the top few per cent of earners. By mathematically modelling historical data, Turchin finds that as population grows, workers start to outnumber available jobs, driving down wages. The wealthy elite then end up with an even greater share of the economic pie, and inequality soars. This is borne out in the US, for example, where average wages have stagnated since the 1970s although gross domestic product has steadily climbed.
In other words, the population of employers—according to this theory—is growing faster than the population of workers.
This process also creates new avenues – such as increased access to higher education – that allow a few workers to join the elite, swelling their ranks. Eventually this results in what Turchin calls "elite overproduction" – there being more people in the elite than there are top jobs. "Then competition starts to get ugly," he says.
I don't think he can have it both ways.
On the gripping hand …
… there actually is a little bit of evidence in favor of this theory. There is a tendency for eras with frequent war (e.g., the first half of the 20th century) to have few revolutions and eras with frequent revolutions (e.g., most of the 19th century) to have few wars. (On the fourth hand, we can have wars and revolutions at the same time in transitional eras.) We can think of revolutions as due to lower classes trying for more and wars as due to upper classes trying for more.
Looked at this way, recent history goes from a revolutionary era (1945–1980) to a war era (1980–2010) and more recently back to a revolutionary era. This fits the aborted war in Syria (Syria retains the revolution) and the recent shutdown looks like a fight between two revolutionary parties.