Cold War: The "war" between the Soviet Union and the United states, which ran from 1945 (or so) to the end of the 80s.  The "war" is cold and in parenthesis because it did not involve direct military action between the two countries.  Instead, the "war" was fought by 1) an arms race (he who ends up with the most nukes wins) and 2) by proxy: i.e. in/through other countries with the Soviets or Americans supporting one or the other side.  In Vietnam, the communist North was supported -- surprise, surprise -- by the Soviets, and the South was supported by the United States.