The election of Donald Trump creates extraordinary uncertainty about the future course of U.S. economic policy. Markets don’t like extreme unknowns, and there are valid reasons to fear that Trump’s policy proposals on trade and our economic alliances would be seriously disruptive to the global economy. Global stocks fell sharply when signs of a Trump victory emerged Tuesday, but by mid afternoon Wednesday U.S. stocks were up as markets found their footing on hopes of fiscal stimulus. Meanwhile, U.S. Treasury yields were up and the Mexican peso weakened. It is reasonable to expect that substantial market volatility will be the norm in coming weeks.