The legal confusion over tariffs has buffeted U.S. trading partners around the world, casting doubt on the durability of Trump’s favorite bargaining tool.

Economic growth will slow this year and next as the trade war hampers development in the United States and around the world, the Organization for Economic Cooperation and Development said.

US president Trump has signed an order doubling tariffs on imported steel and aluminum to 50%, citing national security concerns and aiming to protect domestic industries from foreign dumping. While tariffs on UK imports remain at 25%,