Personally, I think the key problems in the U.S. that have caused such sharp polarisation are ignorance of world issues and their importance and an unjustified attitude of hostility toward a global market, economy and community coupled with the continued refusal of the patriarchal establishment to accept women as equals in society.
If you ask, for example, how such radical wing nuts have managed to come to the forefront of the GOP, you can blame ignorance and entirely unjustified egocentrism on the part of the yokels voting for them as well as misogyny in more extreme (and recently publicised) cases. When it comes to the economy, you can blame the sweeping deregulation ushered in by our last fabulous president and the self-serving attitudes of all the people at the top who stood to profit from it. Not to mention the fact that all of the biggest corporations have laid off scores of workers during the recession and then posted record profits, the fact that women still don't make 3/4 of what men do and the fact that the average worker's salary has actually decreased in the last 25 years while inflation and the cost of living have soared. That fits in because of the fact that all of those CEO's, politicians and hedge fund managers did not care and do not care about the effects of their actions not only on the U.S. but on the global economy. It also fits in because the same ignorant hordes were supporting this once again. If there was widespread understanding of and outrage over such policies, on top of countless others, I don't think funneling all the money in the world into the news and campaigns of the people responsible would have resulted in their being elected. Keeping people stupid and scared keeps things running smoothly for the ultrarich.
