Gerald Seib: “Listen to the early sounds of the 2016 presidential campaign, in which candidates of the left and the right sound almost identical populist, anti-Wall Street, antiestablishment themes, and the idea doesn’t seem so crazy. When you have Republican presidential contenders opposing free-trade agreements, and at least one backing an increase in the minimum wage; when Democratic firebrand Bernie Sanders (technically an independent to begin with) is speaking to overflow crowds; and when left and right come together to halt a prominent national-security program backed by the foreign-policy establishment—well, something is going on.”

