I think this comment from Stiglitz: What the IMF Must Do to Reestablish Legitimacy clearly states the complication of international trade.
This poses a dilemma for Chinese policy makers. Subsidising their own farmers would divert money from education, health, and development projects. Or China can try to maintain an exchange rate that is slightly lower than it would be otherwise. If the IMF is to be even-handed, should it criticise American farm policies or China’s exchange-rate policies?