DONALD TRUMP took North America to the precipice of a trade war over the weekend. On February 3rd he cooled things down, delaying tariffs on Canada and Mexico by a month as the countries attempt to reach a deal that may involve everything from immigration controls to trade concerns. The sudden about-turn underscored Mr Trump’s reputation as an agent of chaos who uses extreme threats to wrest concessions out of others. It is a dangerous game that can just as easily lead to miscalculations and corrosive uncertainty for the global economy.