It is a paradox that tariffs, which to some extent counter the free market, can be used to demonstrate the free market.Tariffs can be for protectionist reasons. They can also function as a user fee similar to road taxes, airport landing fees, postage stamps, and national park admission. Increased trade is great, but the port workers are not volunteers, and somebody has to fund the cost of the port personnel. International trade is often multi-modal with railroads and highways transporting freight after the ship or cargo plane arrives in the United States, but the ports need the infrastructure including any upgrades to handle the quantity and size of the cargo ships, the airports also need to be able to handle the cargo planes which land, and should goods be shipped from Canada or Mexic
