Free Trade and Mana from Heaven
Here is the ultimate test if you are truly against free trade. Suppose tomorrow Jesus, Moses, Abu Bakr, etc. comes before the heads of the world and declares that henceforth mana from heaven will arrive three times a day to feed the world's population, curing world hunger with no effort. Would this be good for our society? What about the people in the meat, baking, agricultural industry who would lose their jobs? How do you think they will feel about it?

This hypo show the dramatic problem of free trade - even when as a whole society would better off, some still lose, making it in their interest to maintain (if possible) the old status quo.