President Donald Trump on Thursday imposed once unthinkably high U.S. taxes on imports from dozens of countries, part of his campaign to turn one of the world’s most open economies into a fortress bristling with barriers to trade.

Most of the new duties kicked in Thursday, hitting countries with elevated rates that mark a departure from long-standing trade norms.

Mexican President Claudia Sheinbaum has extradited cartel leaders, deployed troops to the border — and remained calm. So far, it’s worked.