America has always been attracted to rebelliousness, but things have reached the state of being pathological.
The tea-party has picked up on the R's political impedance and contrariness, typified by Norquist's "no new taxes, shrink government" and Mitch McConnell's approach. Now the republican base, which cannot grasp the principles involved, simply walks around looking for a fight, with one or more 'Don't Tread on Me' flag magnets stuck to their cars, and tattooed on their arms.
What they mostly want to fight is anything that is status quo--except of course they don't want to change to status quo of belligerence.
In the face of amazing amounts of dry powder seemingly unreasonably held in reserve, the left has also developed an appetite for belligerence and confrontation.
Across America, around kitchen tables, in conference rooms and in legislatures there is no respect, no recognition of alternate views, no interest in searching for compromise that captures the best of both points of view. It's all or nothing and very serious.
Many of the politicians, political pundits, and even DU'ers use language so deeply embedded in defensiveness that it suggests existential desperation. Intolerance is growing.
We are in a social environment where competitive debate replaces discussion and where debate is nothing but verbal combat. It seems to have been brought about by the approach of one political party determined to have its way, either by winner-take-all outcomes or refusal to cooperate. But, as argued by Adam Curtis, in "The Power of Nightmares", it could also have arisen from fundamental religious rhetoric, not only in America, but also in the Eastern Mediterranean.
After decades of this, the distinction of chicken vs egg arguments seems less important than recognition of the current increasingly unstable state of affairs here.
As a society we've drawn up sides, we dream of conflict, and we practice arguments that will justify conflict.