But, more fundamentally, the nihilism and the craziness and the destructiveness that we see going on with the "extremists" within the Party represents a fuller flowering of what the Republican Party establishment sowed and cultivated.
The Tea Party was not part of Congress until 2011. But by then, we'd already had two years of Republicans in opposition taking the unprecedented step of making it their top priority to make the new president fail, to prevent anything good from being accomplished even if that meant voting against their own ideas.
The Tea Party should be understood, I believe, in two main ways:
1) In its top-down (astro-turf) dimension, it represents the deliberate effort of the most cynical components of the right-wing force (like the Koch Brothers, who put forward the money to launch it, and like Rupert Murdock's news empire, which publicized it into prominence) to enable the Spirit of Destructiveness to take further possession of the Republican Party.
The disease is systemic. The uprising of the nihilists is a natural result of the choice of the Republican Party, increasingly over the past generation, to make deals with the devil.