The International Economy magazine (Winter 2013) asks 16 authorities, “Can Changes in Exchange Rate Valuations Affect Trade Imbalances?“ It is referring to the claim in a recent book by Stanford economist Ron McKinnon that pressure on China to let the renminbi appreciate against the dollar is fundamentally misconceived because such a movement in the exchange rate would not reduce China’s trade surplus nor American’s trade deficit. This is part of an old debate that pre-dates the rise of the China trade problem. Ron has& long claimed that exchange rates don’t determine trade balances because they are “instead” determined by national saving versus investment. I thought PaulKrugmandemolished the argument pretty effectively 25 years ago, with a textbook graph of internal balance versus external balance. But evidently many still fall for the argument (including some of the experts in the TIE symposium). So I try again:
Ron McKinnon has made many important contributions to international macroeconomics over the years. But on this issue, he is simply wrong.
It goes without saying that the current account is equal to the difference between national saving and investment. But it does not follow that we should try to improve the current account in the short run by increasing national saving. Under current conditions, that would send the United States back into recession.
The national saving identity is a tautology: it does not in itself imply causation. True, many of the big movements in the U.S. current account deficit can be explained by changes in national saving: the fiscal expansion of the early 1980s, the investment boom of the late 1990s, and the new fiscal expansion of the 2000s. But the important point is that we care about a lot of things besides just external balance (the trade balance and current account). We care at least as much about internal balance (growth, employment, and inflation). To say that an increase in the budget balance and national saving would improve the trade balance does not imply that this would be good policy or that it is the only way to improve the trade balance.