CAMBRIDGE – America's two political parties rarely agree, but one thing that unites them is their anger about “currency manipulation," especially by China. Perhaps spurred by the recent appreciation of the dollar and the first signs that it is eroding net exports, congressional Democrats and Republicans are once again considering legislation to counter what they view as unfair currency undervaluation. The proposed measures include countervailing duties against imports from offending countries, even though this would conflict with international trade rules.
This is the wrong approach. Even if one accepts that it is possible to identify currency manipulation, China no longer qualifies. Under recent conditions, if China allowed the renminbi to float freely, without intervention, it would be more likely to depreciate than rise against the dollar, making it harder for US producers to compete in international markets.
But there is a more fundamental point: From an economic viewpoint, currency manipulation or unfair undervaluation are exceedingly hard to pin down conceptually. The renminbi's slight depreciation against the dollar in 2014 is not evidence of it; many other currencies, most notably the yen and the euro, depreciated by far more last year. As a result, the overall value of the renminbi was actually up slightly on an average basis.
The sine qua non of manipulation is currency-market intervention: selling the domestic currency and buying foreign currencies to keep the foreign-exchange value lower than it would otherwise be. To be sure, the People's Bank of China (PBOC) did a lot of this over the last ten years. Capital inflows contributed to a large balance-of-payments surplus, and the authorities bought US dollars, thereby resisting upward pressure on the renminbi. The result was as an all-time record level of foreign exchange reserves, reaching $3.99 trillion by July 2014.