Concern is mounting that the Chinese currency, the yuan, may be misaligned, threatening the stability of the global economy.
The yuan could be 40% undervalued, some say
US Treasury Secretary John Snow is to travel to Beijing next week to express his government's concern that the yuan may be dangerously undervalued.
On Wednesday, the US National Association of Manufacturers (NAM) argued that the dollar was 15% overvalued, and particularly blamed the cheap yuan for causing job losses in American factories.
The yuan is pegged at about 8.3 in the dollar, a rate the NAM said was up to 40% undervalued, giving China's exporters an unfair advantage and making its imports expensive.
Many economists argue that China should allow the yuan to float freely on international markets, or at least should rethink the value of its dollar peg.
Money, money, money
The obvious sign of the undervaluation of the yuan, say observers, is China's swelling national accounts.
The country's dramatic success in export markets has made it a magnet for foreign currency; in July alone, its foreign-exchange reserves jumped $10bn to almost $360bn.
Mr Snow faces an anti-China lobby at home
At the same time, the US has started to record a gigantic trade and current-account deficit with regard to China, something that has aroused considerable political anger.
The situation is analagous to the 1980s, when a similar external position with then-booming Japan sparked a flurry of complaint.
This time, the problem is more widespread: although China is the biggest target, US manufacturers see most major Asian currencies are undervalued.
No complaints here
There are few signs that an appeal from Mr Snow will have any effect in Beijing, however.
Within China, there is little complaint or comment about the exchange rate.
The yuan has underpinned China's boom
Indeed, most Chinese firms and policy makers have welcomed the cheap yuan, seeing it as helping to underpin the country's long economic boom.
Despite its increasing involvement in international agencies such as the World Trade Organisation, China is still reluctant to fall into line on economic policy.
And some independent economists have said that China would be rash to let the yuan float too soon.
Freeing the exchange rate would necessitate sweeping monetary liberalisation, which would almost certainly result in an influx of speculative investment capital - the sort of "hot money" that helped cause the pan-Asian financial crisis of 1997-98.