Apple reclaimed its crown as the world’s most valuable company on April 9th. Financial markets roared higher in response to President Donald Trump’s decision to put a 90-day hold on his “reciprocal” tariffs to most countries, but not China. Look past the euphoria, though, and there is a stark reality. More than most big American firms, Apple remains hugely exposed to the worsening trade conflagration with China. Moreover, a pause is just a pause. Mr Trump’s capriciousness still makes it a nightmare to decide how to reconfigure supply chains in a trade war.