So far, the Trump administration’s trade policy has seen an internal division among economic nationalists and “globalists” on the president’s senior staff. The economic nationalists, and the president himself, believe protectionism will strengthen the American economy. “Look at the 19th century,” said former White House chief strategist Steve Bannon in his recent “60 Minutes” interview. “What built America’s so called ‘American system,’ from Hamilton to Polk to Henry Clay to Lincoln to the Roosevelts? A system of protection of our manufacturing, financial system that lends to manufacturers, OK, and the control of our...