Eisenhower's stint as the president of Columbia University was punctuated by his activity within the Council on Foreign Relations, a study group he led as president concerning the political and military implications of the Marshall Plan, and The American Assembly, Eisenhower's "vision of a great cultural center where business, professional and governmental leaders could meet from time to time to discuss and reach conclusions concerning problems of a social and political nature". What sort of analysis did Eisenhower first experience with the Council on Foreign Relations?