The ink had barely dried on Donald Trump’s order to impose a 10% tariff on imports from China before its leader, Xi Jinping, was reaching for his “assassin’s mace” to strike back. On February 4th, in addition to new tariffs, the Chinese government listed several rare metals as controlled exports, giving Mr Xi the power to ban shipments to America at a moment’s notice. The riposte underscores an essential difference between American and Chinese power: Mr Trump’s ability to coerce comes largely from what America buys and its dominance of international finance, while Mr Xi’s far more nascent coercive strength is based on what China sells.