It is remarkable how the world's short history of floating exchange rates has affected popular thinking about what is eternally normal and proper in the economic system. Recently, China-bashing US Senators Charles Schumer and Lindsey Graham wrote matter-of-factly that: "One of the fundamental tenets of free trade is that currencies should float."

Such a "tenet" would have been considered monstrous by most of the economics profession up until the last three decades of the 20th century, prior to which money accepted across borders had generally been gold, or claims on gold, for about 2,500 years. Even John Maynard Keynes, the arch-slayer of the last remnants of commodity money, was an adamant supporter of fixed exchange rates.