Playing chicken with the global economy

I get it - we need to fix the structural problems associated with the US budget.  However, don't these geniuses realize that threatening to default (let alone actually defaulting) on the US sovereign debt will severely undermine the dollar?  It's like they actually want to have hyperinflation, so that they can claim it was all Obama's fault.  Other countries don't have a  "debt ceiling", you know.  Update:  seems I'm not alone in realizing that even talking about default is dangerous.