Ever since the colonial days, isolationism was a popular belief amongst the population. Colonies were inhabited with people that had come from many European countries where religious persecution, poverty and war were common. They wanted to scape all that and an opportunity to start over, so they had to remain isolated from the old world.
Predsident George Washington conclude all aliances and promulgated an isolationist foreing policy that was well accepted by americans, in which he stated: "The great rule of conduct for us, in regard to foreign nations, is in extending our commercial relations, to have with them as little political connection as possible. .... it must be unwise in us to implicate ourselves in the ordinary combinations and collisions of her (Eurepe) friendships or enmities."
This perspective remained active all throughout the 19th Century and the beginning of the 20th. Even though, the United States participated in World War I, the numerous deaths and economic loses supported the cause of isolationists. This strengthen the isolationist foreign policy a few more decades.
It was not until the mid-20th Century when everything changed, Japan attacked Pearl Harbor on on December 7, 1941. Germany and Italy declared war a few days after, and Americans were officially at war and tradicional isolationism was discarded.
