Every time the President talks about trade negotiations, it makes the news. On July 18, he mentioned – for the umpteenth time – that he might prefer to break NAFTA up into two agreements, and the press went ballistic again. We have hundreds of major issues in United States politics – taxes, unemployment, crime, foreign policy – and people can talk comfortably about them because they are always on the collective mind. But trade is different; it’s only an issue once every generation or so. So this is an issue with tons of misconceptions, not only in the electorate, but...