Donald Trump’s trade policies become more shocking

Donald Trump’s assault on trade is escalating. First the foes were China and Mexico. Now it is the world.

The Trump transition team has mooted an import tariff of 10pc across the board, doubling down on earlier talk of a 5pc duty. This is a sobering demarche. Such thinking is of a different character to Mr Trump’s campaign rhetoric, which mostly hinted at trade sanctions to force concessions.

A catch-all tariff is a change of belief systems. It overthrows the free trade order that has been upheld and policed by Washington since the 1940s.

Congress cannot stop Mr Trump imposing his will by “executive action” under existing US law. The historic irony is that Capitol Hill delegated powers to the White House in order to cut tariffs and reach deals, free from meddling by pork barrel interests. Few ever supposed that these same powers might be used to curb trade.

The president may impose tariffs…