What was Mario Draghi up to? Even 10 days after the European Central Bank chief's speech at the annual central bankers' jamboree at Jackson Hole, nobody is quite sure—not the markets, nor policy makers in Berlin, Brussels, Paris, nor even many of his colleagues.
To most observers, his call for governments to allow fiscal policy to play a greater role in pulling the currency bloc out of its slump came out of a clear blue sky. Like most central bankers, Mr. Draghi has tended to avoid commenting on fiscal policy beyond...