Re: The Political Pendulum
While there are swings, I think they operate on a much longer timeframe. For instance, we are still in the Reagan swing that was a reaction to the FDR swing. From crest to crest we're talking around 50 years -- roughly, two generations. If true the next liberal swing should be well underway around 2030, which means I'll be living the rest of my life in the sort of America I like -- payment for having had to suffer through the last several decades of conservative craptasm. Unless, of course, the energy in the system is decreasing, leading to shorter, smaller swings
There may be several independent pendula. So, swings between isolation and intervention, between plutocracy and egalitarianism, etc., all on different cycles.
There seem to be two trends that are simply background conditions that don't swing back and forth: towards social liberalism and towards an upwards concentration of political power. But both may be the result of trends in population and mobility which happen to have increased over the nation's history. A reversal in population or mobility could lead us back to localized power and parochialism.
Edit: from your follow-up I see you are talking about perceptions. On that I don't agree with the model -- perception is so highly subjective and personalized that I'm not sure one can say anything about it as trending, except for things like the boiling frog metaphor where a gradual but steady move in one direction provokes far less alarm and negative perception than a sudden jolt (for example, the gradual adoption of fringe right wing theories and proposals has now led us to where 60% of Trump supporters support what is prima facie an unconstitutional and spectacularly evil policy of religious discrimination, or the gradual movement on LGBT rights that had continually moved the goalposts on germane political issues).