[WS:] Great posting, thank you.
To play devil's advocate, however, my experience is that the US has a rather large group of people questioning the status quo - from politics to morals and everyday life conduct. More so that I've seen in Europe. Yet, this critical thinking does not seem to form a critical mass, so to speak, but instead it is marginalized and goes nowhere. So what really needs to be explained is why political dissent is so easily marginalized in the US, and for that matter most English speaking countries.
My hypothetical answer is based on distinction between two types of democracy - "majoritarian" and "consensus" proposed by Arendt Lijphart ("Patterns of Democracy" http://wikisum.com/w/Lijphart:_Patterns_of_democracy). To make a long story short, in the majoritarian (first past the post) democracy developed in England and colonies, minority interests are systemically neutralized and marginalized to the so called "median voter" (http://en.wikipedia.org/wiki/Median_voter_theorem) which is another term for the greatest probability of winning elections in a two party majoritarian system. In the 'consensus' democracy by contrast, no single party can win required majority, political cooperation of minorities is required to form winning coalitions.
The end result is that minority interest in 'consensus' democracy do get recognition and legitimacy and sometimes even political representation. In The US/British system, by contrast, minority interests are dismissed as "fringe" and disruptive to the electoral process (and rightly so!). For such interest to get any political traction at all, they need to be willing to go ballistic and threaten the status quo if they do not get a seat at the table. In a consensus democracy they would get that seat without such extraordinary measures. That may help explain the political behavior of the Repug party. It is a rational response to an outdated and rather undemocratic political system of representation originally devised by British aristocracy and landowners. In other words, the right wing wingnuts have no illusions that they are a minority and to get any traction they need to terrorize the system into compliance. Liberals, on the other hand, have a delusion that this is the greatest democracy on Earth and all they need to do is keep playing by the book. An analogy can me made to a poker game in which a player with a moderately strong hand keeps bidding, but then a player with a a pair of deuce bluffs by betting a very large amount, betting (quite rationally) that the other guy's hand is not as strong as to risk getting into a bidding war. At the end, they with a pair of deuce wins. Ditto for the Repug politics in the majoritarian system.
In conclusion, the only way Democrats can win this game is to form a wingnut wing of their own that threatens to throw a few monkey wrenches into the political gears. But in the long run, this will only expose the fundamental dysfunctionality of the US electoral system that systemically marginalized minority interests in a country with one of greatest diversity of interests on this planet.
Wojtek