Use of China’s $2.4 trillion reserves to challenge US foreign policy is fraught with problems, not least because any damage to America will recoils immediately against China – which depends on the US market for its mercantilist growth strategy. Beijing cannot stop accumulating dollars unless it is willing to let the yuan ride, eroding the margins of its export industry. Some reserves can be parked in gold or even copper, but liquid commodity markets are not big enough to absorb the scale of Chinese surpluses.