US president Donald Trump’s threat to hit car imports with punitive tariffs risks sparking global retaliation against as much as $300 billion of US products, Brussels has warned. The warning is the first time that the European Commission, in a written submission to the US Department of Commerce seen by the Financial Times, has set out a detailed response to Mr. Trump’s threat to slam punitive tariffs on imported vehicles, with EU capitals increasingly convinced that the unpredictable US president will act soon. Mr. Trump on Sunday said that the EU was “as bad” as China when it came to...