America under President Donald Trump sometimes looks like a command economy. Its elite talks effusively about doing business with the state: the great-power struggle will be lost to China unless America intervenes in commerce like its rival, runs the argument. Mr Trump routinely declares war on the prices of things, from mortgages to petrol to stocks. Yet for a system which is now often described as veering into state capitalism, the state has proved surprisingly ineffective at bending markets to its will. Mortgage rates are stubbornly high. So are petrol prices. The stockmarket has the whip hand over the White House, rather than the other way round.
