The yield curve for Treasury bonds inverted on Wednesday, and that sparked a major stock sell-off as well as rampant speculation about the state of the economy. While it is true that inverted yield curves preceded each of the last seven recessions, the phenomenon is a symptom and not a cause. It is sometimes a warning signal of other causes, such as overly tight monetary policy. For example, when monetary policy is too restrictive and short-term rates are high, the market pushes long-term rates down. However, that is not the current situation. Inverted yields are also sometimes a symptom of fundamental weakness or worries over uncertainty, which is most definitely the case now. The yield curve inverted briefly in December 2018 as trade tur...