International finance has always been one of the more elusive areas of economics, in part because the channels through which capital moves around the world are so tortuous that the system looks as if it had been thought up by Rube Goldberg. It’s not surprising, therefore, that among all the various forces and factors to be blamed for the current global economic crisis — deregulation, Alan Greenspan, credit-default swaps, the power of the financial lobby, excessive leverage, securitization, Wall Street greed — the most difficult to get one’s head around is the international monetary system.

It has long been recognized that the global financial structure — built as it is around the dollar as the world’s reserve currency — has a fundamental design flaw that makes it inherently unstable. The problem was first identified back in the early 1960s by the Belgian-American economist Robert Triffin, in “Gold and the Dollar Crisis.” Writing about Europe’s accumulation of dollars, he argued that the system carried the seeds of its own destruction. Foreigners could acquire dollars only if the United States ran current account deficits — that is, spent more than it earned. But lending money to someone who lives beyond his means has obvious dangers, and the same is true of countries. Thus, the American deficits necessary to supply dollars to the world for international transactions simultaneously undermined confidence in the currency. It was only a matter of time, Triffin predicted, before the system would be hit by a crisis — which it duly was in the early 1970s.

At the beginning of the current decade a group of commentators, the most ­articulate being the Financial Times columnist Martin Wolf, updated Triffin’s critique and applied it to current arrangements. Whereas Triffin had been primarily concerned about the European accumulation of dollars, the spotlight was now on Asia. In the wake of the 1997 financial crisis there, countries in East Asia set out to build up war chests of dollars as insurance against domestic banking runs or downturns in the global economy. At about the same time, China embarked on a program of export-led growth, engineered by keeping its currency artificially low.

Interpretations of what happened next differ. Some argue that to absorb these goods from abroad while avoiding unemployment at home, the United States very consciously stimulated consumer demand. The country, in effect, was forced to live beyond its means. Others believe that the Fed misread the fall in prices as a symptom of inadequate demand rather than for what it was — an astounding, once-in-a-generation expansion in the supply of low-cost goods — and kept interest rates low for an unusually long time, which provoked the real estate bubble.