How can I protect myself from a Global Currency?

If the American USD Dollar is replaced with a Global currency as has been proposed, and our Sec. of Treasury stated he would not be opposed, can I stipulate in a legal published doent that all of my contracts will be null and void unless in USD $ as when the contracts were signed? The Amero was proposed as one of ten regional currencies issued by a New Global Bank. The SPP is still in effect, moving us toward a North American Union. Yes, I have heard that the International Bankers have decided against that name for the currency, but not the issuance of the regional currencies. Can my lenders require payment in any new currency foisted upon us?