section_path: History/19th century
section_name: 19th century
paragraph_text: 19th century
  
  In 1817, David Ricardo, James Mill and Robert Torrens showed that free trade would benefit the industrially weak as well as the strong, in the famous theory of comparative advantage. In Principles of Political Economy and Taxation Ricardo advanced the doctrine still considered the most counterintuitive in economics:
  
  The ascendancy of free trade was primarily based on national advantage in the mid 19th century. That is, the calculation made was whether it was in any particular country's self-interest to open its borders to imports.
  
  John Stuart Mill proved that a country with monopoly pricing power on the international market could manipulate the terms of trade through maintaining tariffs, and that the response to this might be reciprocity in trade policy. Ricardo and others had suggested this earlier. This was taken as evidence against the universal doctrine of free trade, as it was believed that more of the economic surplus of trade would accrue to a country following reciprocal, rather than completely free, trade policies. This was followed within a few years by the infant industry scenario developed by Mill promoting the theory that the government had the duty to protect young industries, although only for a time necessary for them to develop full capacity. This became the policy in many countries attempting to industrialize and out-compete English exporters. Milton Friedman later continued this vein of thought, showing that in a few circumstances tariffs might be beneficial to the host country; but never for the world at large.