President Trump has identified global postal rates, administered by the UN’s UPU, as the latest front in the American government’s attempts to rein in Chinese exports. A review of American strategy towards the rates, which treat China as an emerging market and so eligible for low postal rates, is due from Secretary Pompeo by November 1. A move to raise rates would be minor compared to duties already applied on $250 billion of Chinese exports. U.S. imports of “low value” items from China were worth $3.4 billion in the 12 months to July 31. While that was 1.3x the levels traded with eac...