(New York Times) The United States stock market might be worth nearly $2 trillion more if not for the trade war. Consider that the cost that investors appear to be ascribing to President Trump’s efforts to upend decades of trade relationships. Typically, it’s hard to know why stocks are up or down over short periods. And the 5.8 percent gain in the Standard & Poor’s 500-stock index this year might seem to be one of those inscrutable moves. But a closer look at the factors that usually drive the stock market suggests that the escalating trade tensions are holding stocks back.