From global trade deals to the South China Sea, America and China look set for a series of almost inevitable collisions, as the world’s pre-eminent power tries to come to grips with the rise of its leading challenger. But must the relationship between the world’s two largest economies turn more conflictual, both economically and militarily, and does America’s more assertive recent Asia policy, most notably its attempts to reassert its position in the South China Sea, make this more likely?