During 1936-37, the bloc of aggressive powers-Germany, Italy and Japan- had emerged. It had been strengthened by the policy of appeasement followed by major Western powers, notably Britain and France. The US also remained indifferent to the various acts of aggression committed by these countries. The policy of appeasement continued, and Hitler was convinced that his invasion of Poland, which precipitated the war in September 1939, would not provoke Britain and France into action. This appeasement policy can be considered as a major driving force for the second world war.