To me it seems that the abruptness of the US defaulting on its loan payments would send the economy into quite a substantial shock, likely worse than what we saw in 2007. Further, that this came about from a plurality of elected officials is even more alarming.
However, the US has "defaulted" once before, and it was arguably because of the executive action of even less men. See this article (http://en.wikipedia....iki/Nixon_Shock) for information on how Nixon took the US off of the gold standard in 1971 (maybe to fund a war in Vietnam?).
As a radical libertarian, I see the removal of government influence in any industry a welcome thing. However, I am not sure if this is the way to go about it, i.e, through an engineered, short-notice crisis, rather than through the gradual changes and concessions technologies like cryptography have obliged the government to accept.