LESS THAN two weeks into his new administration, Donald Trump has placed large tariffs on America’s three biggest trading partners—raising the spectre of a global trade war. With executive orders signed on February 1st, he initiated tariffs of 25% on imports from both Canada and Mexico, and added levies of 10% to imports from China. Although Mr Trump had vowed to do just this, his actions will still represent a shock to the global economy. They will drive up prices, weigh on growth and sow uncertainty for businesses. Moreover, they are likely to be just the first salvo for Mr Trump, who is itching to implement tariffs that are both more aggressive and more global.