From the Telegraph
"Given the key position occupied by US Treasuries in the world's money system, the effect of such a default would be like a death star exploding. It would be Lehman Brothers to the power of a thousand. Indeed, the effect would be so calamatous that nobody can quite believe it will ever be allowed to happen. The idea behind Mutually Assured Destruction (MAD) was that use of nuclear weapons would be equally devastating to both sides; their existence therefore guaranteed the peace. The threat of US default is a similar sort of thing. Congress can quarrel all it likes about Obamacare, but it is presumably not about to take the blame for returning the world economy to the stone age. It will surely come to its senses."