Donald Trump announced and then postponed punitive tariffs of 25% on goods from Canada and Mexico. The American president is using the threat of tariffs to press both countries to stop the flow of migrants and fentanyl across the border. He granted a 30-day reprieve following urgent talks with Claudia Sheinbaum, Mexico’s president, and Justin Trudeau, Canada’s prime minister. Both leaders promised to boost their border security. Both had earlier vowed to retaliate with tariffs of their own on American products. The European Union said it would also retaliate after Mr Trump said he would “definitely” impose tariffs on EU imports over America’s trade deficit with the region. Global markets shuddered.