To judge by the build-up to Hu Jintao's America visit this week, one would be forgiven for thinking the health of US-China relations was measured solely by the renminbi's dollar value.

On this, President George W. Bush, who usually paints America's choices in black and white, is subtler than some of his critics, having conceded US-China relations are "complex". That characterisation might equally apply to Mr Bush's often contradictory stance towards China since taking office.