A historic global trade war, a proposed $1.2 trillion European fiscal bazooka and the emergence of China as tech race leader are upending global flows of money, marking a potential turning point for investor capital away from the United States. China unlocked more stimulus on Wednesday and promised greater efforts to cushion the impact of an escalating U.S. trade war. Meanwhile, U.S. economic data points to a weakening, and the trade war unleashed by U.S. tariffs that kicked in this week is hurting sentiment inside and outside the world's biggest economy.For most of the last three years, investors had bet on "U.S. exceptionalism," with the country ahead of others in economic growth, stock prices, artificial intelligence and other areas.