> And until the shock, national currencies circulated at a fixed exchange with the USD - thereby his own currency was effectively gold backed?
Yes, "effectively gold-backed" until the first guy came along to openly demand an actual physical (rather than "potential") exchange of USD reserves for real ounces, in size, from the US. Bam, Nixon shock. Essentially "caused" by one "individual Frenchman" (de Gaulle) testing whether the system can in fact, in size and in physical actuality consistently deliver what it promised to the world.