Answer: policy of containment was a strategy initiated by Harry Truman in relation to post-war Soviet expansionism. But the author of this doctrine was George Kennan who was well experienced in Soviet and central European policy and diplomacy. He was well aware of imperialist intentions of Russians. Whereas Americans withdrew their forces from many countries immediately after the war, Russians kept their armies there also during the new elections etc etc. Soon, these countries got Communist government. Whereas in Europe division line between USSR and the West became Berlin. Vietnam and Korea became clearly another division line, this time in Far East. This time Americans did not want to repeat erros the did in Eastern and Central Europe....which led to the division of both countries. Conflict was the result of the containment policy ....Americans were ready to defend free society in South Korea.
Explanation: containment was a strategy that started being used immediately after the Marshall Plan (economic help of USA to devastated peoples of Europe) which was offered even to USSR. Containement was based on the assumption of Soviet expansionism which was motivated also by Lenin´s and Marx´s belief in the inevitable world Communist revolution. Do not forget - for many USSR was very popular at that time.