In the first 50 days of his second term, President Trump’s penchant for imposing and then suspending tariffs has shaken markets and confounded trading partners.

Increased tariffs on all U.S. steel and aluminum imports took effect on Wednesday, as Trump steps up his campaign to reorder global trade in favor of the United States. Europe swiftly retaliated. Trump’s plans for tariffs – and their back-and-forth implementation since he took office in January – have upended industries from cars to energy and unnerved businesses and investors.