Answer: the Truman doctrine was established in 1947 which was American foreign policy, this means that it is a policy that will describe how America will cooperate with foreign countries. This policy established that US would provide political, military and economic assistance to all democratic nations under threat.
The long telegram was the wide ranging analysis of Russian policy which Kennan gave to US concerning the reason why Russians opposed the creation of the World Bank and the international monetary fund. Kennan was US embassy in Moscow then.
Containment was a US policy which involves using various strategies to prevent the spread of communism. Literally containment means keeping something restricted or under control or to prevent a hostile country from expanding it's influence.
United Nations was formed on October 24, 1945. The organization was formed was founded to safeguard democracy, freedom and peace in the aftermath of Nazism and World War II.
UN is necessary because it is a common venue for nations to try and workout their problems diplomatically and when necessary take collective action.
US is part of UN this is necessary because US been the world power has a great role to play to keep nations at peace.
World War II pulled America out of depression due to the amount of money spent on explosive during the war, this made a great impact on spending, taxes. So the end of World War II marked the end of depression for America.
Depression didn't return because the employment market produced profits and savings which in turns meant further investment.
Europe was freed even more from the American influence. This subjected Europe to increasing Soviet influence.
Iron curtain was formally known as a non physical boundary dividing, Europe Into separate areas from the end of World War II until the end of the cold war.
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