Wall Street's main indexes fell on Friday after U.S. President Donald Trump recommended 50% tariffs on the European Union, while Apple slid after he warned the company would have to pay tariffs if iPhones were not made in the United States.

Now they have a trade war problem to worry about again. Stocks fell Friday after President Donald Trump brought the trade war back to the forefront with threats of massive tariffs against America’s most valuable company and one of its most important trading partners.

The sprawling bill, which would slash US taxes and increase spending, is the centrepiece of the president’s second-term agenda and has been at the centre of a fierce battle among Republicans in the Ho...