Just when the world economy was showing signs of positive stability, up popped Donald Trump with import tariffs on aluminium and steel. Given that the North Americans refuse to keep the second ‘i’ in aluminium, and insist on alumi‘num’, one is in good company in describing the entire thing as dumb: “It’s dumb” is how esteemed US economist Larry Summers described Trump’s crazy move. Summers also questioned why the errant US President would want to penalise his allies in the name of national security. “The tariffs are the most irrational economic policy that any President has introduced in the last half century” is how Summers sees what will benefit a tiny number of US citizens and penalise the rest.