mark is wrong on one count....US treasuries DO have a de-facto guarantee within the jurisdiction of the US govt. this doesn't mean their value is gauranteed, the value of the bond may fluctuate with a variety of factors...but, US treasuries can be redeemed with created accounts by a 1982 law, making them the fiat equivalent of the US dollar itself. whether you can do anything with those dollars is another issue, but thats not an assurance issue, its a trade issue