No one familiar with the Smoot-Hawley tariff of 1930 should relish the prospect of a trade war with China — but that seems to be where we're headed and is probably where we should be headed. Although the Smoot-Hawley tariff did not cause the Great Depression, it contributed to its severity by provoking widespread retaliation. Confronting China's export subsidies risks a similar tit-for-tat cycle at a time when the global economic recovery is weak. This is a risk, unfortunately, we need to take. In a decade, China has gone from a huge, poor nation to an economic colossus. Although its...