Democrats had just absorbed a crushing defeat in the 1994 midterm elections when President Bill Clinton’s very liberal labor secretary, Robert Reich, ventured into hostile territory to issue a prophetic warning.Struggling workers were becoming “an anxious class,” he told the centrist Democratic Leadership Council, two weeks after Republicans led by Newt Gingrich had gained 54 seats in the House and eight in the Senate. Society was separating into two tiers, Mr. Reich said, with “a few winners and a larger group of Americans left behind, whose anger and whose disillusionment is easily manipulated.”“Today, the targets of that rage are immigrants...