One of the reasons why I think the Modern West is in decline is because the political theory upon which it is premised is based on a misunderstanding of human nature. One of the great fallacies which is incorporated into western political and legal theory is the myth of the "rational man". By which I mean, the theory that the average man is a sober and reflective judge when it comes to political judgment. The myth is actually a composition of two fallacies:
1) The effective doctrine that each man's political deliberation is just as valid as another's. This denies the validity of experience, study and IQ.
2) The myth that men are impartial judges of data. Whereas in reality both conservatives and liberals "filter" away data that is inconvenient and effective have a rationalisation hamster that justifies their beliefs in the face of contradictory evidence.
One of the hardest things to do, when attempting to think, is to try and eliminate one's biases from one's reasoning. It is possible, but what it requires is a devotion to the totality of data present and not filtering data away which is inconvenient.
For example, I am an anthropogenic climate change skeptic. Not because I have some emotional agenda which I want to keep intact, rather its because the totality of the data that I have seen makes the CO2 argument appear a bit weak. Now the Medieval warm period had lower CO2 levels than today. This in itself does not invalidate the CO2 argument, since it is quite possible that there are several mechanisms of climate change, and good scientist trying to understand how climate actually works will acknowledge this. He will not try to deny data which is inconvenient to his preferred theory, rather he will modify his theory to incorporate the data. When a scientist tries to "hide the decline" I know that he is more committed to his ideology than to understanding the truth.
Its not a scientific paper but a good article (from the left wing perspective) of how a lot of people are "biased" when it comes to processing information.
The truth of the matter is that the majority of the population "feel-think" instead of "truth-think" and and any political theory or constitution which fails to take this into account is a bit like an civil engineering course which neglects soil mechanics: It's going to eventually fail.
Our political process has not been corrupted as a result of outright conspiracy, the problem is more fundamental. As political power is passes from the few to the many, the likelihood of policy being decided on sentiment instead of reason becomes greater. Feel good policies become predominant over are-good policies.
Perhaps the reasons why democracies eventually fail is because, by becoming every more inclusive, they become incapable of making the hard decisions that ensure their survival. Universal suffrage paves the way for political instability.