That is a very insightful posting, indeed. Of course, WW II was full of switching sides. Consider the Soviet General Vlasov (http://www.plp.org/books/Stalin/node117.html) and the Nazi General von Paulus (http://www.spartacus.schoolnet.co.uk/GERpaulus.htm) who reneged against their own countries, apparently to settle own personal scores. Of course, switching sides took place on a much lower as evidence by the so-called Volks-deutsch, or Poles who claimed their "German roots" during WWI and opted for a quasi German citizenship, the Waffen SS consisting of renegade Lithuanians, Ukrainians, etc. Or simply folks turning their neighbors in (Jewish or otherwise) for money or to settle personal scores.
If there is anything as "human nature" it is most likely to be conformism and risk aversion, as aptly illustrated in Alberto Moravia's novel _Il Conformista_ whose protagonist become a fascist collaborator out of conformity. I have seen that in many Polish immigrants who were staunched Communist Part members while in Poland, and became staunch Reagan supporters in the US. That makes me believe that the great majority of people would suck up to any authority - capitalist, communist, fascist, Islamic, Christian, etc. out of their conformism, fear, or greed.
PS. It's nice to be back in the Wild West - those Euro prices were really hurting.
Wojtek