Trade wars invariably involve government actions intended to impede, punish or prevent imports and exports of goods between two or more countries. The most common ammunition used by participants is the imposition of higher tariffs and/or surcharges on either imports of specific items or on an across-the-board basis. Such disputes were relatively common during the 19th century when trade was viewed as a government-sponsored competition between or among nations. Perhaps the most famous trade war occurred in 1930 when the U.S. Congress passed the Smoot-Hawley Act. It raised U.S. tariffs on imports of more than 20,000 items to the highest level since the 1820s after they had already been increased in 1922. Many countries responded by raising t...