Assuming we are on our way to a resolution of the China currency dispute, what caused the situation to improve so rapidly, when not long ago the rhetoric was getting quite heated? Dan Drezner sets out some possibilities, along with his view:
If China's shift is a real one, there appear to be three possible sources of change:
1) Domestic factors and actors convinced China's leadership that diminishing marginal returns for keeping the yuan fixed and masively undervalued had kicked in;
3) China responded to threats of unilateral U.S. action, such as being named as a currency manipulator, and/or calls for a trade war;
These are not mutually exclusive arguments, and we might never know exactly what caused China's [change]. But for the record, I think (1) and (2) mattered a hell of a lot more than (3). That said, I can't rule out the possiblity that their antics helped scare China into action.