The White House, eager to win a trade war it barely understands, has yanked the emergency brake on China-US trade without checking who’s inside the vehicle. Donald Trump’s early April trade decree has taken a month to hit the economy – that’s how long Chinese containers need to reach Los Angeles. And on cue, US pacific ports registered a 45% drop in container bookings this week from China. When warehouses fall quiet and trucks idle in California, the silence will creep eastward. Unemployment will surely tick upwards. Even if Washington reverses course by the end of May, and Beijing plays...